(;
GM[1]
SZ[19]
AW[qm][pm][nc][nd][cn][gd][jf]
AB[jp][jd][pj][dj][dp][pd][pp][dd][cf][fp][qn][oc][pf][nj]
TR[jf]
C[Problem 1. Black to play.  

White seems to be staking out a large territory at the top by capping with her marked stone. Black must run out into the center, but on which side: the right or the left ? ]
(;B[ie]
TE[2]
C[Correct Answer.  

Playing towards the left with the diagonal move of Black 1 is in the correct direction. ]
;W[gf]
C[If White jumps to 2, ... ]
;B[if]
C[... Black pushes out with 3. ]
;W[ig]
C[If White tries to block Black's march into the center with 4, ... ]
;B[jg]
C[... Black will cut with 5. ]
(;W[hg]
C[If White 6 next, ... ]
;B[kf]
C[... Black catches a stone with 7. The two white stones at the top right are now in trouble. <= ]
)
(;W[kf]
C[Variation.  

If White draws  back with 6, ... ]
;B[hg]
C[... Black ataris with 7 ... ]
;W[ih];B[hf]
C[... and connects at 9. White's two stones on the left are now in trouble. ]
;W[gg]
C[If White 10, ... ]
;B[hh]
LB[ii:B][gh:A]
C[... Black plays 11, leaving the points A and B as miai. <= ]
))
(;B[le]
C[How the game continued.  

Black 1 was in the wrong direction. ]
;W[nf]
C[White jumped to 2, ... ]
;B[lg]
C[... forcing Black to jump to 3. ]
;W[lb]
C[White then made a base for her stones with 4. Even though Black's stones have escaped into the center, they are thin and White will look for a chance to attack them. This is a good strategy for White in a handicap game: first strengthen your position, then wait for a chance to attack. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gp][qf][mg][pm]
AB[jp][jd][pj][dj][dp][pd][pp][dd][nd][dn][nq]
TR[mg]
C[Problem 2. Black to play.  

Jumping out into the center with the marked stone is a bold move, but it is really an overplay because White's position is too thin. How can Black seize the initiative ? ]
(;B[og]
TE[2]
C[Correct Answer.  

Black should separate the two white stones by jumping between with 1. ]
;W[of]
C[If White tries to link up by attaching with 2, ... ]
;B[nf]
C[... Black plays 3 ... ]
;W[ng];B[pf]
C[... and 5. ]
;W[pg]
C[Against the double atari of White 6, ... ]
;B[oh]
C[... extending to 7 is the key move. ]
;W[pe]
C[White captures with 8, ... ]
;B[oe]
C[... but Black secures the corner with 9 ... ]
;W[pf];B[qd]
C[... and 11; White's stones at the top are nearly dead. <= ]
)
(;B[nj]
C[How the game continued.  

Jumping to Black 1 cannot be called a bad move. It certainly keeps the weak white stones above and below separated. ]
;W[ld]
C[However, by not attacking directly, Black gave White the chance to play another move at the top with 2. Fierce fighting later ensued through which White settled her stones at the top and gained some profit. <= ]
)
)
(;
GM[1]
SZ[19]
AW[md][nc][oc][pc][qb]
AB[jp][jd][pj][dj][dp][pd][pp][dd][od][nd][ne][qc]
TR[qb]
C[Problem 3. Black to play.  

How should Black respond to the marked white stone ? ]
(;B[rb]
TE[2]
C[Correct Answer.  

The two-step hane of Black 1 is an effective move in this position because of the cutting points in White's group. ]
;W[rc]
C[If White goes after the black stone in the corner with 2 ... ]
;B[qd]
(;W[ra]
C[... and 4, ... ]
;B[mc]
C[... Black cuts with 5. ]
;W[sb]
C[If White captures with 6, ... ]
;B[lc]
C[... Black extends to 7 and gets massive thickness in the center. <= ]
)
(;W[pb]
C[If White plays 4 here, ... ]
;B[rd]
C[... then capturing a stone with the atari of 5 is big for Black. <= ]
))
(;B[rc]
LB[rb:@][qd:A]
C[How the game continued.  

Being afraid of the cut at A, Black descended to 1. This was a passive move. Depending on later developments, White @ might be a strong move, so Black's position on the right cannot be considered thick. ]
;W[cn]
C[In the meantime, White played 2 ... ]
;B[fp];W[dg]
LB[qd:A]
C[... and 4 on the left side leaving the cut at A as aji. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gd][cn][nc][pb][qb][qc][qd][qf][qg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dg][fp][ld][ob][oc][pc][pe][pf]
TR[qg]
C[Problem 4. Black to play.  

How should Black respond after White extends with the marked stone ? ]
(;B[pg]
TE[2]
C[Correct Answer.  

Two ways to maintain your advantage in high-handicap games are to keep your handicap stones connected and to force White's stones into a low position, while maintaining a high profile towards the center with your own stones. Black 1 achieves both these objectives. ]
;W[ph]
C[The hane of White 2 is unreasonable. ]
;B[qe]
C[Black plays 3 to create defects in White's position, ... ]
;W[re];B[qh]
C[... then cuts with 5. ]
;W[oh]
C[If White extends to 6, ... ]
;B[rh]
C[... Black forces with 7 ... ]
;W[rg];B[sg]
C[... and 9, ... ]
;W[rf];B[pi]
C[... then settles the lower right side with 11. White's stones in the center are floating without a base and they will become a good target for Black to attack. <= ]
)
(;B[dn]
C[How the game continued.  

Black attached at 1 in the lower left. Since Black was strong around there, White didn't have a good move locally. A good strategy for White in handicap games is to play where her prospects are best. ]
;W[pg]
TR[pj]
C[Since turning at 2 was a strong move, this is where she played. White's position on the right was now thick and the marked stone, being close too close to this thickness, lost much of its power. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qm][pm][nc][nd][cn][gd][jf][nf][lc]
AB[jp][jd][pj][dj][dp][pd][pp][dd][cf][fp][qn][oc][pf][nj][le][lg]
TR[lc]
C[Problem 5. Black to play.  

This is a continuation of Problem 1. How should Black respond to the marked stone ? ]
(;B[je]
TE[2]
C[Correct Answer.  

Black can make shape by bumping against the white stone 1. ]
;W[kf]
C[After exchanging 2 ... ]
;B[lf]
C[... for 3, ... ]
(;W[hf]
C[... White must defend with 4. ]
;B[ld]
C[Next, Black makes a thick shape with 5. White is thin on both the left and the right, so at least one of these groups will come under attack. <= ]
)
(;W[ke]
LB[hf:@]
C[If White pushes in with 4 here instead of @, ... ]
;B[kd]
C[... Black blocks with 5. ]
;W[ld]
C[If White cuts at 6, ... ]
;B[if]
C[... Black hanes with 7. This will be an easy fight for Black. <= ]
))
(;B[kd]
C[How the game continued.  

Black 1 made bad shape. ]
;W[mh]
C[White moved out into the center with 2 ... ]
;B[og];W[lh]
C[... and 4. ]
;B[kg];W[jb]
LB[mh:2][og:3]
C[Black 3 threatened to cut off the stone at 2, but White settled her stones by sliding to 6, ... ]
;B[ic];W[lj]
LB[og:3][jb:6]
C[... then reinforcing the ones in the center by jumping to 8. Note how White didn't merely link up after Black 3; instead she took the initiative by expanding her positions with 6 and 8. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gp][qf][pm][ld][pg][mg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][nd][dn][nq][pf][nj]
LB[pf:1][pg:2]
TR[ld]
C[Problem 6. Black to play.  

After White played the marked stone in Problem 2, Black attached with 1. How should he answer White 2 ? ]
(;B[qe]
TE[2]
C[Correct Answer.  

Blocking with Black 1 secures the corner. ]
;W[of]
C[White has no choice but to atari with 2, ... ]
;B[pe];W[qg]
C[... then connect with 4. ]
;B[qi]
C[Black strengthens his position with 5 on the right side, preventing White from making a base there and forcing her to make eyes in the center. Next, ... ]
;W[dg]
LB[dg:??]
C[... (White ?? is necessary here to get "Black to move") ... ]
;B[me]
C[...  Black is threatening to split White in two with the sequence from Black 7 ... ]
;W[le];B[mf];W[lf];B[ng]
C[... to Black 11.  <= ]
)
(;B[of]
C[How the game continued.  

The extension of Black 1 enabled White to make a wall ... ]
;W[og];B[qe];W[qg];B[nf];W[ng]
LB[qc:A]
C[... with the sequence to 6. Whereas White's stones were previously thin, they were now thick. Moreover, Black ended this skirmish with bad aji at A. See Problem 10 for the continuation.  <= ]
)
)
(;
GM[1]
SZ[19]
AW[md][nc][oc][pc][qb][cn][gd][dg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][od][nd][ne][qc][cl][rc]
LB[gd:2][cl:1]
TR[cn]
C[Problem 7. Black to play.  

This is a continuation of Problem 3. Black 1 restricted the movement of the marked stone, so White plays elsewhere, making an approach with 2. How should Black answer ? ]
(;B[ef]
TE[2]
C[Correct Answer.  

Black 1 keeps the two white stones separated. ]
;W[eg]
C[White first pushes up with 2, ... ]
;B[ff];W[dc]
C[... then counterattacks by attaching with 4. ]
;B[ec]
C[Black hanes with 5, ... ]
;W[ed]
C[... but White responds strongly by crosscutting with 6. ]
;B[fd];W[fc];B[eb];W[fe];B[ee]
C[After Black 11, ... ]
;W[fd]
C[... White connects with 12 and ... ]
;B[cc];W[de];B[cd];W[fb];B[db];W[df]
C[... the sequence to 18 is inevitable, but Black is alive in the corner and, ... ]
;B[gf]
C[... when he extends to 19, White is in trouble. ]
(;W[ie]
C[If White goes for the top with 20 ... ]
;B[gh];W[je]
C[... and 22, ... ]
;B[ei]
LB[gh:21]
C[... Black will secure the upper left side with 21 and 23. Moreover, White still needs another move to secure the top. <= ]
)
(;W[ei]
C[On the other hand, if White plays 20 here, ... ]
;B[ie]
C[Black will play 21 and the six white stones at the top left are in trouble. <= ]
))
(;B[lc]
C[How the game continued.  

Black attacked the stones in the upper right with 1 ... ]
;W[mc];B[lb]
C[... and 3, ... ]
;W[ld]
C[... but White forced with 4, ... ]
;B[jc];W[lf]
C[... then jumped to 6. Black's moyo on the right was no longer impressive and his stones at the top become heavy. See Problem 11 for the continuation. <= ]
)
(;B[me]
TR[jd]
C[Variation.  

In Black wants to play on the right, driving White towards the marked stone with 1 ... ]
;W[ld];B[le]
C[... and 3 is the right direction. Black's moyo on the right is huge. ]
(;W[kd]
C[White must not play 4 ... ]
;B[ke]
C[... because she will be short of liberties after Black 5. <= ]
)
(;W[ke]
C[If White hanes at 4, ... ]
;B[kd]
C[... White's stones at the top are in danger after Black 5. <= ]
))
)
(;
GM[1]
SZ[19]
AW[gd][cn][nc][pb][qb][qc][qd][qf][qg][pg][oh][nh][nk][nn][pn][qm][qo]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dg][fp][ld][ob][oc][pc][pe][pf][dn][og][mg][ng][pl][np][po][qn]
LB[qm:14][po:13][qo:12][qn:11][nn:10][pl:9][nk:8][np:7][pn:6]
TR[pg]
LB[mg:5][nh:4][ng:3][oh:2][og:1]
C[Problem 8. Black to play.  

After White turned with the marked stone in Problem 4, Black played 1 and the sequence to 14 followed. How should Black play next ? ]
(;B[rn]
TE[2]
C[Correct Answer.  

Descending to Black 1 and taking the corner ... ]
;W[pm];B[rm];W[rl];B[ql];W[rk];B[ol];W[nm];B[qp]
C[... taking the corner with the sequence to 9 is big. ]
;W[nl]
LB[nj:B][rj:A]
C[White's territory above is not yet secure because of the bad aji of A. If Black can play somewhere around B, this aji will come to life.  <= ]
)
(;B[on]
C[How the game continued.  

Black linked up with 1 ... ]
;W[rn];B[om]
C[... and 3, but ... ]
;W[qq]
C[... White took the corner with 4, gaining more territory than in the Correct Answer. Black's stones were now thin and ... ]
;B[dc]
LB[dc:??]
C[... (Black ?? is necessary here to get "White to move".) ]
;W[mp]
C[... White threatened the sequence from White 6 ... ]
;B[no];W[mq];B[nq];W[jr];B[iq];W[ir];B[hr];W[kp]
C[... to White 14. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cg][dg][eg][cn][dn][gm][hj][qf]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fj][co][fp][cf][df][fe][nd]
TR[hj]
C[Problem 9. Black to play.  

White has just capped with the marked stone. How should Black escape into the center ? ]
(;B[gi]
TE[2]
C[Correct Answer.  

Black should move out with 1, putting pressure on the three white stones above. ]
;W[gg]
C[White escapes with 2, ... ]
;B[hi]
C[... but Black is safely out in the center with 3. ]
(;W[ig]
C[If White 4, ... ]
;B[ij]
C[... Black will play 5. Now his stones are thick in the center and the four white ones below will be in danger. <= ]
)
(;W[bj]
C[Therefore, White slides to 4 linking up her stones above and below. Next, ... ]
;B[ij]
C[... Black plays 5. <= ]
))
(;B[hi]
C[How the game continued.  

Attaching with 1 was dangerous. ]
;W[gi];B[fh];W[hh]
(;B[gg];W[ii];B[fi]
C[Black manages to escape with the sequence to 7, but ... ]
;W[bj]
LB[ii:6]
C[... White made a ponnuki in the center with 6 and rescued her stones in the upper left with 8. In the meantime, because of this ponnuki, Black's territories at the top and the bottom became thinner, so this was an unsatisfactory result for Black. <= ]
)
(;B[ii]
LB[gg:@]
C[Instead of @, Black should have extended to 5. <= ]
))
)
(;
GM[1]
SZ[19]
AW[gp][qf][pm][ld][pg][mg][ng][og][qg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][nd][dn][nq][pf][nj][qe][of][nf]
TR[ng]
C[Problem 10. Black to play.  

How should Black play after White connects with the marked stone in Problem 6 ? ]
(;B[nm]
TE[2]
C[Correct Answer.  

The lone white stone in the lower right is thin, so Black should attack it by capping with 1. In this way, he can strengthen his own weak stones while attacking White's. ]
;W[qp];B[qq];W[po];B[op];W[ro]
C[White makes sabaki with the sequence to 6. ]
;B[rq]
C[After Black 7, ... ]
(;W[ql]
C[... White can live by simply extending to 8. <= ]
)
(;W[qj]
C[White's stones die.  

If White attaches at 8, ... ]
;B[qk];W[pk];B[qi];W[rj];B[rk];W[ri];B[pl];W[ok];B[ol]
(;W[oj];B[nk];W[oi]
LB[nk:19]
C[... her stones in the bottom right die with the sequence to Black 19. <= ]
)
(;W[nk]
LB[oj:@]
C[If White plays 18 here instead of @, ... ]
;B[rh];W[qh];B[pi];W[rg];B[sj];W[sh];B[mk]
C[... White's loss will be even bigger after the sequence to Black 25. <= ]
)))
(;B[jf]
C[How the game continued.  

Black jumped to 1 at the top, but ... ]
;W[ok]
C[... White took the initiative on the right side by peeping at 2, ... ]
;B[oj];W[lj]
C[... then capping at 4. <= ]
)
)
(;
GM[1]
SZ[19]
AW[md][nc][oc][pc][qb][cn][gd][mc][ld][lf][dg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][od][nd][ne][qc][cl][rc][jc][lc][lb][fp]
TR[lf]
C[Problem 11. Black to play.  

White jumped out into the center with the marked stone in Problem 7, threatening Black's moyo on the right and the four black stones at the top. How should Black respond ? ]
(;B[jf]
TE[2]
C[Correct Answer.  

Black must jump to 1, strengthen his four stones. ]
;W[lh]
C[White answers by jumping to 2. ]
;B[gf]
C[Next, Black attacks on the left with 3 and ... ]
;W[ee];B[ed];W[fe];B[de];W[fg]
C[... White makes shape with the sequence to 8. ]
;B[jh]
C[The black stones at the top still have to escape, so Black jumps to 9. ]
;W[og]
C[If White 10, ... ]
;B[qg]
C[... Black is satisfied to defend at 11. ]
(;W[df]
C[If White 12 next, ... ]
;B[gc]
C[... Black can link up ... ]
;W[hc];B[gb]
C[... with the sequence to 15.  <= ]
)
(;W[nq]
LB[nq:??]
C[Continuation after the Correct Answer.  

White plays elsewhere (White ?? is necessary here to get "Black to move") ... ]
;B[ef]
C[After Black 11 in the Correct Answer, Black can take the territory on the left side ... ]
;W[ff];B[eg];W[eh];B[df];W[fh];B[ch]
LB[dh:B][cg:A]
C[... with the sequence to 19. The points A and B are miai for Black. <= ]
))
(;B[ng]
C[How the game continued.  

Black jumped to 1 and, ... ]
;W[jf]
C[... when White capped at 2, ... ]
(;B[gb]
C[... slid to 3. ]
;W[fc]
C[The sequence ... ]
;B[fb];W[ec];B[cc]
C[... to Black 7 followed. This was bad for Black.  <= ]
)
(;B[if]
C[Black should have attached at 3 here. ]
(;W[ig]
C[If White haned at 4, ... ]
;B[hf];W[je];B[hd]
C[... the sequence to Black 7 would most likely be played and Black would end up with good shape.  <= ]
)
(;W[jg]
LB[ig:@]
C[Therefore, White should have simply extended to 4 (instead of @).  <= ]
)))
)
(;
GM[1]
SZ[19]
AW[fq][lp][pm][nj][qf]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dn][np][nf][nd]
TR[lp]
C[Problem 12. Black to play.  

White invades the bottom with her marked stone. How should Black answer ? ]
(;B[nn]
TE[2]
C[Correct Answer.  

Black should jump to 1, threatening to pull out the black stone an the right and keeping the white stone on the left isolated. ]
;W[ol]
C[If White defends with 2, ... ]
;B[ko]
C[... Black 3 all but captures the white stone at the bottom right. ]
(;W[jq]
C[If White tries to make sabaki with 4 ... ]
;B[iq];W[ip]
C[... and 6, ... ]
;B[hq]
C[... White has no follow-up after Black extends to 7. <= ]
)
(;W[lr]
C[If White jumps down to the second line with 4, ... ]
;B[jr]
C[... Black blocks from the left with 5. ]
;W[oq];B[pq];W[op];B[oo];W[nq];B[pr];W[mp];B[no];W[jq];B[iq];W[kq];B[ip];W[kr];B[ir];W[ns]
LB[nn:1]
C[With the black stone at 1 present, White just barely lives with the sequence to 20, but ... ]
;B[dq]
C[... Black takes an unassailable lead when he encloses the lower left corner with 21. <= ]
))
(;B[lo]
C[How the game continued.  

Black attached with 1 ... ]
;W[mo];B[mp];W[ko];B[lq];W[ln];B[kp]
LB[ln:6]
C[... and linked up with the sequence to 7, but White made a ponnuki with 6, which gave him tremendous power in the center. ]
;W[ch]
C[White ended in sente, so she switched to the left side with 8. See Problem 16 for the continuation of this game. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pm][nj][nh][og][qf]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][nq][oh][ng][nd]
LB[qf:1][nd:2][pm:3][nq:4][nj:5][oh:6][nh:7][ng:8][og:9]
C[Problem 13. Black to play.  

White cuts with 9. How should Black respond ? ]
(;B[ph]
TE[2]
C[Correct Answer.  

The proverb advises, 'When caught in a crosscut, extend !'. Black should follow this maxim by extending to 1 and strengthening his stones toward the edge. This gives him two ways to save his stones on the side. ]
(;W[mh]
C[If White extends to 2, ... ]
;B[pg]
C[... Black ataris with 4. ]
;W[qc]
C[It is unreasonable to try and save the stone in atari, so White might jump to the corner with 4. ]
;B[qd]
C[Black will block with 5 and ... ]
;W[rd];B[re];W[rc];B[qe];W[ob];B[nb];W[oc];B[nc];W[od];B[oe]
C[... confine White to the corner with the sequence to 15. ]
;W[pc]
C[White ends in gote, so ... ]
;B[ok]
C[... Black can separate White's stones in the center from the one on the side with 17. For this reason, White won't invade at 4 immediately. Instead, she will leave it in reserve as aji and strengthen her stones in the center first. <= ]
)
(;W[of]
C[Variation.  

If White extends to 2 first, ... ]
;B[ni]
C[... Black ataris from the other side with 3 and ... ]
;W[mh];B[mi]
C[... pushes out into the center with 5, building a wall and influence towards the bottom. ]
;W[lh];B[nf]
C[Black 7 now leaves White with two weak groups to defend. This result is bad for White. <= ]
))
(;B[ni]
C[How the game continued.  

Black 1 ... ]
;W[mh];B[mi]
C[... and 3 were unrelenting, but ... ]
;W[oi]
C[... they gave White the chance to counterattack with 4 ... ]
;B[ph];W[pi]
C[... and 6. In the fight to 26, Black made many mistakes - ... ]
;B[pg]
LB[qi:A]
C[... - 7 should be at A - ... ]
;W[qi];B[pf];W[mg];B[nf]
LB[li:B]
C[... - 11 should be at B - ... ]
;W[li];B[mj];W[mk];B[lj];W[kj];B[lk];W[kk];B[ll];W[kh];B[ji];W[ki];B[nl]
LB[oj:C]
C[... - 23 should be at C - ... ]
;W[oj];B[nk];W[ok]
C[... - so White got profit on the right and established a position in the center. This sequence was a success for White. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][cf][oi][ph][qf][qc][pc][oc][nc][od]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][lc][fp][nh][nd][ne][oe][pe][qd]
TR[oi]
C[Problem 14. Black to play.  

White tries to escape into the center with the marked stone. How should Black attack ? ]
(;B[mj]
TE[2]
C[Correct Answer.  

Jumping ahead of the white stones with the knight's move of Black 1 ... ]
;W[oj]
C[... forces White to run away with 2 ... ]
;B[pl];W[ok];B[qj];W[ol]
C[... to 6, ... ]
;B[pm]
C[... thereby inducing Black to make territory along the fourth line with the sequence to 7. ]
;W[ml]
C[You might think that White is home free when she jumps to 8, ... ]
;B[kl]
C[... but Black can continue the attack by capping at 9. ]
(;W[mo]
C[If White jumps to 10, ... ]
;B[pq]
C[... Black secures territory on the right with 11. <= ]
)
(;W[lk]
C[If White 10 here, ... ]
;B[jj]
C[... Black keeps White hemmed in with 11. White will have trouble making two eyes. <= ]
))
(;B[ni]
C[How the game continued.  

Black pushed with 1. This was a bad move ... ]
;W[oj];B[pk]
LB[ol:B][pn:A]
C[... because after Black 3 White can counterattack around A, inducing Black B. However, ... ]
;W[nj]
C[... White must first turn at 4. White now has more options in her run to safety in the center. See Problem 18 for the continuation of this game. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][fm][dg][gg][hd]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][fj][hj][fp]
LB[cn:1][fp:2][dg:3][fd:4][fm:5][fj:6][gg:7][hj:8][hd:9]
C[Problem 15. Black to play.  

White invades the top with 9, isolating the two black stones and hoping to start a fight around here. How should Black respond ? ]
(;B[ig]
TE[2]
C[Correct Answer.  

Black 1 is a severe attack. Besides mapping out a large moyo in the upper right, it threatens to split White's overstretched stones. ]
;W[hf]
C[White 2 ensues a connection between her stones, but ... ]
(;B[ce]
C[... Black 3 robs them of their base white securing the territory in the corner. <= ]
;W[if])
(;B[if]
C[If Black wants to emphasise his moyo, he will block with 3. ]
;W[cd]
C[White would then attach at 4. <= ]
))
(;B[fb]
LB[cd:A]
C[How the game continued.  

Black defended the corner with 1, but this move was off the mark. White's stones on the left could still make a base by attaching at A. ]
;W[nd]
C[White switched to the upper right with 2, putting pressure on the two black stones at the top. ]
;B[ld]
C[Black tries to alleviate this pressure by making a checking extension to 3, but ... ]
;W[nf]
C[... after exchanging 4 ... ]
;B[pf]
C[... for 5, ... ]
;W[jh]
C[... White attacked on a large scale with 6. See Problem 19 for the continuation of this game. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fq][lp][pm][nj][qf][ko][ln][mo][ch][eh]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dn][np][nf][nd][lq][kp][mp][cf]
LB[cf:1][eh:2]
C[Problem 16. Black to play.  

This is the continuation of the game in Problem 12. Black exchanged 1 for White 2. How should he continue ? ]
(;B[cj]
TE[2]
C[Correct Answer.  

Black 1 defends the territory on the lower left, preventing any white countermeasures there. ]
;W[fd]
C[If White switches to the top with 2, ... ]
;B[fe]
C[... Black can attach with 3. ]
;W[ge];B[ff];W[ed];B[de]
C[After the sequence to Black 7, the prospects for White's stones on the left area bleak. <= ]
)
(;B[fd]
C[How the game continued.  

Reinforcing the top with Black 1 ... ]
;W[dl]
C[... gave White the chance to play on the left side with 2. See Problem 20 for the continuation of this game. ]
)
)
(;
GM[1]
SZ[19]
AW[cf][hd][fj][dm]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fp][pn][fd]
LB[cf:1][fd:2][hd:7][fj:5][dm:3][fp:4][pn:6]
C[Problem 17. Black to play.  

Black ignores White's cap at 5 and strengthens his position in the lower left  with 6. How should Black respond to White's invasion at 7 ? ]
(;B[ge]
TE[2]
C[Correct Answer.  

Black should play the diagonal move of 1 and aim to confine White to the top ... ]
;W[he];B[hf];W[if];B[ie];W[hb];B[jb]
LB[ec:B][kc:A][hb:6]
C[Note Black 7. After White 6 in this joseki, White can live on the side by playing at either A or B. Driving White into the corner and confining her there, where she can do the least strategic damage, is the correct choice for Black. ]
;W[ec];B[ed];W[fc];B[dc];W[gd];B[gf];W[db];B[cb]
C[... with the sequence to 15. ]
;W[ea]
C[White lives with 16, but, ... ]
;B[dg]
C[... when Black plays 17, he gets territory on the left side and has foiled White's capping strategy. <= ]
)
(;B[cd]
C[How the game continued.  

Black defended the corner with 1. This was a reasonable move, ... ]
;W[ef]
(;B[gc]
C[... but Black 3 was bad. He did gain some territory in the corner, but ... ]
;W[hc]
C[... it induced White to increase her influence on the right with 4. Black was still left with the problem of how to deal with White's two stones at the top. <= ]
)
(;B[fm]
LB[cd:a]
C[Instead of a in the upper left corner, Black 1 here would also be a good move. <= ]
)
(;B[ge]
C[Black should have simply played at 3 here. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cn][cf][oi][ph][qf][qc][pc][oc][nc][od][pn][nj][oj]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][lc][fp][nh][nd][ne][oe][pe][qd][pk][ol][ni]
LB[pn:1][ol:2][nj:3]
C[Problem 18. Black to play.  

In the game in Problem 18, instead of playing  the honest move of 3, White exchanged 1 for Black 2, then turned at 3. What should Black do now ? ]
(;B[on]
TE[2]
C[Correct Answer.  

Attaching with Black 1 is severe. ]
(;W[po];B[oo];W[qp];B[qq];W[pq];B[op];W[rq];B[qr]
(;W[rr];B[pr];W[ro]
C[White just barely lives with the sequence to 12, but the wall Black has made will have a strong effect on White's stones above. ]
;B[lj]
C[Black has sente so he starts an attack on these stones with 13. <= ]
)
(;W[ro]
C[Variation. ]
;B[rr];W[sr]
C[White plays the sequence to 12, hoping to live in sente, ... ]
;B[oq];W[lj]
C[... then jumps to 14. ]
;B[qn]
C[However, Black attaches at 15 and ... ]
;W[qm];B[pm];W[qo];B[rm];W[ql];B[rn];W[sn];B[rl];W[qk];B[rk];W[qj];B[qi];W[rj];B[ri]
C[... White's stones in the lower right die with the sequence to 29. <= ]
))
(;W[qq]
LB[on:1]
C[Variation.  

In response to Black 1, White might invade the corner with 2. ]
;B[qp]
C[Black blocks with 3, ... ]
;W[pq];B[rq];W[rr];B[rp]
LB[rq:5]
C[... then hanes and connects with 5 and 7. ]
;W[nq];B[op];W[mr]
C[White lives in the corner with the sequence to 10, but ... ]
;B[mj]
C[... Black plays 11, attacking the five stones on the right side. ]
;W[nl];B[mk];W[nk];B[lm];W[om];B[pm];W[nm];B[qn];W[nn]
C[When White plays 20, ... ]
;B[np]
C[... Black stops her from linking up to her stones at the bottom with 21. Now the white stones have no way to escape. <= ]
))
(;B[ml]
C[How the game continued.  

Black jumped to 1 and ... ]
;W[lj]
C[... White escaped into the center with 2. ]
;B[nn]
C[Black capped with 3, but ... ]
;W[qq];B[pq];W[qp]
(;B[po];W[qo];B[on];W[mc];B[ld];W[pm]
LB[np:A]
C[... White easily lived in the corner with the sequence to 12. In addition, Black still has some bad aji at A which White might be able to exploit later. <= ]
)
(;B[qr]
LB[qp:6]
C[Variation.  

After White 6, ... ]
;W[rr];B[pr]
LB[qr:7]
C[... Black could have haned and connected with 7 and 9. ]
;W[rn];B[rs];W[sr]
LB[np:C][oo:B][po:A]
C[After White 12, Black ends in sente as before, but White's territory in the corner is smaller and Black's aji at the bottom is good. If White A or B, Black will jump to C. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cn][fm][dg][gg][hd][jj][im][nd][ne][nf][nh][jh][kb][lc][kd][ke][le][md]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][fj][hj][fb][pg][lh][jf][je][jc][kc][me][mf][lf][kf][fp]
TR[im]
C[Problem 19. Black to play.  

The game in Problem 15 eventually reached this position. White has just played the marked stone, threatening to engulf the three black stones. How should Black respond ? ]
(;B[hh]
TE[2]
C[Correct Answer.  

Black should first exchange 1 ... ]
;W[hg]
C[... for White 2, ... ]
;B[fg]
C[... then attach with 3. ]
;W[ff]
C[If White 4, ... ]
;B[ef]
C[... Black hanes with 5. ]
(;W[eg]
C[If White next ataris with 6, ... ]
;B[fh]
C[... Black draws back with 7. <= ]
)
(;W[fh]
C[If White 6, ... ]
;B[eg];W[eh];B[gh]
C[... the sequence to Black 9 follows. In either case, White's stones are in tatters. Even if she manages to save one group, the other will die. <= ]
))
(;B[ch]
C[How the game continued.  

Black tried to live on the side with 1 ... ]
;W[cg];B[dh]
C[... and 3. This is usually a bad decision in an open position such as this because White can strengthen her stones and this will have a negative impact on the black stones in adjacent areas. ]
;W[eg]
C[In this game, White strengthened her stones with 4, denying Black the chance to cut through and link up to the top. ]
;B[fh];W[eh]
C[White 6 ... ]
;B[ei];W[bh]
C[... and 8 gave Black bad shape. ]
;B[bi]
C[If Black 9 next, ... ]
;W[bf]
C[... White will connect loosely with 10. ]
;B[cj]
C[Black must fix up his shape with 11, so ... ]
;W[cc]
C[... White can live and destroy Black's territory in the corner by jumping to 12. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fq][lp][pm][nj][qf][ko][ln][mo][ch][eh][dl][cj]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dn][np][nf][nd][lq][kp][mp][cf][fj]
LB[dl:1][cj:3][fj:2]
C[Problem 20. Black to play.  

In the game in Problem 16, White exchanged 1 for 2, then attached at 3, aiming to link up his stones on the left side. How should Black deal with this move ? ]
(;B[di]
TE[2]
C[Correct Answer.  

Black should let White link up along the side and push through in the center with 1 ... ]
;W[ci];B[dh]
C[... and 3. ]
;W[dg];B[cg];W[dk];B[fi]
C[With the sequence to 7, White manages to link up some of her stones and get a small bit of territory on the left, but, in return, Black gets a thick position and territory in the upper left. <= ]
)
(;B[ck]
C[How the game continued.  

The hane of Black 1 was a black move. ]
;W[dk]
C[After White cut with 2, ... ]
;B[di]
C[... Black found his stones short of liberties after 3 ... ]
;W[ci]
(;B[dh]
C[... and 5, so ... ]
;W[dg];B[fi]
C[... he had to defend at 7 ... ]
;W[cg]
C[... instead of being able to cut at 8. See Problem 24 for the continuation of this game. <= ]
)
(;B[fi]
LB[dh:@][dg:6]
C[The Black @ - White 6 exchange was bad. Black should have simply played at 5 here. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cf][hd][fj][dm][hb][hc][ef][eg]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fp][pn][fd][cd][ee][gc][ff]
LB[hb:1]
C[Problem 21. Black to play.  

In the game in Problem 17, White descended to 1. How should Black respond ? ]
(;B[jb]
LB[kc:A]

TE[2]
C[Correct Answer.  

White could settle her stones at the top by jumping to A, so Black should prevent this by confining her to the top left with 1. ]
;W[ge];B[fe];W[fb]
C[The farthest White can enter into Black's territory is 4, but ... ]
;B[db]
C[... Black's stones are in no danger after he defends with 5. ]
;W[hg];B[fg]
C[After 7, White's stones at the top are still without a base and Black is threatening to  turn White's potential Territory on the left into his own, so ... ]
;W[eh]
C[... White will be strongly inclined to defend at 8. ]
;B[el]
C[Even so, Black's stone on the left still has an escape route at 9. <= ]
)
(;B[gb]
C[How the game continued.  

Black was suckered into making another move to defend his corner territory with 1. Having invested so many stones to take this territory, one could understand his urge to defend it, but another way of looking at it is: too many stones have been invested to take a relatively small territory, so his stones are overconcentrated. ]
;W[nc]
C[As a result, White got the jump on Black at the top when ... ]
;B[nd];W[md];B[ne];W[oc]
C[... she took up a position in the upper right with the sequence to 6. ]
;B[pc]
C[In spite of these inferior moves, Black can still deliver a knockout punch. See Problem 25 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][ek][cn][dn][ho][hp][hr][mp]
AB[jp][jd][pj][dj][dp][pd][pp][dd][gc][co][fp][go][gn][jn][qm]
TR[hr]
C[Problem 22. Black to play.  

White jumps down to the second line with the marked stone. How should Black respond ? ]
(;B[jr]
TE[2]
C[Correct Answer.  

This is another example of driving White into the corner by jumping down to 1. This keeps White's forces at the bottom separated. ]
;W[eq]
C[White can live with 2 ... ]
;B[ep];W[fq]
C[... and 4, but the territory she gets is small, ... ]
;B[dq]
LB[jr:1][kq:C][hq:B][gq:A]
C[... while Black's territory in the corner is bigger and more secure. Before playing 1, Black might consider exchanging A for White B, but then might jump to C instead of connecting at B. <= ]
)
(;B[fr]
LB[kq:A]
C[How the game continued.  

Black defended the corner with 1, so White could link up her stones by jumping to A. ]
;W[ko]
C[But she first peeped with 2. ]
(;B[hn]
C[Black strengthened the center with 3, so ... ]
;W[jo]
C[... White took profit with 4. See Problem 26 for the continuation. <= ]
)
(;B[jo]
C[If Black had connected with 3, ... ]
;W[kq]
C[... White would have fallen back to 4, satisfied with making Black's stones heavy. <= ]
)
(;B[kp]
LB[ko:2]
C[Variation.  

In answer to White 2, Black could have crawled to 3. ]
;W[jo]
C[If White pushes in with 4, ... ]
;B[lo];W[lp];B[io];W[kn];B[ip]
C[... the sequence to Black 9 is inevitable. ]
;W[in]
C[If White ataris with 10, ... ]
;B[hn]
C[... Black cuts with 11 and ... ]
;W[jm];B[hq]
C[... secures the bottom left with 13. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cn][co][dm][ek]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][cp][dn][en]
LB[ek:7][dm:3][cn:1][co:5][cp:6][dn:2][en:4]
C[Problem 23. Black to play.  

In this nine-stone game, Black played the attach-and-extend joseki with the sequence to 6. White 7 was an unusual move. How should Black respond ? ]
(;B[ej]
TE[2]
C[Correct Answer.  

Black should push up with 1, ... ]
;W[fk]
C[... forcing White to extend to 2, ... ]
;B[dk]
C[... then turn at 3. ]
(;W[em]
C[If White 4, ... ]
;B[fp]
C[... Black secures the bottom with 5. ]
;W[fj]
C[If White 6 next, ... ]
;B[fi];W[gi];B[fh]
C[... the sequence to Black 9 follows. <= ]
)
(;W[dl]
C[White gets a defective shape is she plays 4 here. <= ]
))
(;B[dk]
C[How the game continued.  

You might think that Black 1 would give the same result as the Correct Answer, but, ... ]
;W[em]
(;B[fm];W[fl]
LB[em:2]
C[... after 2 and 4, ... ]
;B[gm];W[dg]
C[... White attacked the two black stones, which were now heavy, with 6. <= ]
)
(;B[fp]
C[If Black had played 3 here, ... ]
;W[dg]
C[... White would still have attacked with 4. <= ]
))
)
(;
GM[1]
SZ[19]
AW[fq][lp][pm][nj][qf][ko][ln][mo][ch][eh][dl][cj][hc][cg][dg][ci][dk][cm][bo][fk][gl][gn][gp][hp]
AB[jp][jd][pj][dj][dp][pd][pp][dd][dn][np][nf][nd][lq][kp][mp][cf][fj][fd][dh][di][ck][bp][dq][fp][em][iq]
TR[hc]
C[Problem 24. Black to play.  

This is the position eventually reached in the game in Problem 20. How should Black respond to the marked stone ? ]
(;B[jc]
TE[2]
C[Correct Answer.  

Black 1 limits the space in which White can maneuver; it also secures the territory in the top right. ]
;W[he]
C[If White plays 2, ... ]
;B[ff]
C[... Black 3 prevents her from linking up. White is in trouble. <= ]
)
(;B[he]
C[How the game continued.  

Black capped with 1, ... ]
;W[jc]
C[... but White was able to live at the top ... ]
;B[kc];W[id]
LB[he:1]
C[Variation.  

Even Black 1 is a slack move, ... ]
(;B[ie]
LB[jb:A]
C[Variation.  

Blocking at 5 (instead of A) is not as good because White can live at the top ... ]
;W[kb]
(;B[jb];W[ic];B[lc];W[lb];B[mc];W[fb]
C[... with the sequence to 12. Black made a thick wall, but in this position it is unclear how he can turn it into territory. <= ]
)
(;B[kd];W[lb];B[gc];W[ib];B[hd];W[ic]
C[... with the sequence to 12. ]
;B[mc]
C[However, this result is better for Black than the actual game. <= ]
))
(;B[jb]
LB[kc:3]
C[... Black can still take the initiative with 3 and 5. ]
;W[ic]
C[After White connects with 6, ... ]
;B[kd]
LB[he:1]
C[... Black 1 is on the vital point and White's stones are heavy, so they will have a hard time escaping. Moreover, Black has taken control of the territory in the top right. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cf][hd][fj][dm][hb][hc][ef][eg][cp][co][md][nc][oc]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fp][pn][fd][cd][ee][gc][ff][dq][pc][nd][ne][gb]
LB[cp:1][co:3][dq:2]
C[Problem 25. Black to play.  

The game in Problem 21 continued with White 1 and 3. How should Black attack ? ]
(;B[fg]
TE[2]
C[Correct Answer.  

Black should first push with 1, ... ]
;W[eh]
C[... forcing White to defend with 2, ... ]
;B[kc]
LB[el:B][mc:A]
C[... then play die diagonal move of 3, keeping White's stones at the top separated and aiming at the cut at A. White will have a hard time defending both of her groups at the top. You should note that White has still not secured the territory at the side; Black can still pull his stone out by playing at B. <= ]
)
(;B[me]
C[How the game continued.  

Black pressed White against the top ... ]
;W[ld];B[le];W[kd];B[ke]
C[... with the sequence to 5. In some positions, these might be good moves, but in this case Black lost his chance to score a decisive win. ]
;W[jc]
C[White secured all her stones at the top and made some territory there as well. ]
;B[qj]
C[If Black had made an iron pillar with 7, however, this would be a satisfactory result. See Problem 29 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][ek][cn][dn][ho][hp][hr][jo][ko][mp]
AB[jp][jd][pj][dj][dp][pd][pp][dd][gc][co][fp][go][gn][jn][qm][hn]
TR[jo]
C[Problem 26. Black to play.  

This is the position in the game in Problem 22 after White pushed through with the marked stone. How should Black continue ? ]
(;B[ej]
TE[2]
C[Correct Answer.  

Pushing up with Black 1, pressing the three white stones against the black wall below, is severe. ]
;W[fk];B[fj];W[gk];B[gj]
C[Black continues up to 5, ... ]
;W[hk];B[ce]
C[... then plays 7 in the upper left, securing the corner and robbing the lone white stone there of its base. Black has taken a commanding lead. <= ]
)
(;B[io]
C[How the game continued.  

Black wedged in with 1, but this was gote because, ... ]
;W[ip];B[in]
LB[jr:B][jq:A]
C[... after Black connected with 3, Black A would not be a viable threat (White attaches at B and Black loses the capturing race). ]
;W[ej]
C[Therefore, White was able to use her next move to strengthen her position on the left with 4. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][co][dm][ek][ed][ee][dg][cg][gj][gl][fl][em]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][cp][dn][en][cf][eh][gh][ej][dk][fm][gm][hm]
TR[cg]
C[Problem 27. Black to play.  

This was the position eventually reached in the game in Problem 23. How should Black respond to the marked white stone ? ]
(;B[dc]
TE[2]
C[Correct Answer.  

Descending to Black 1 is a solid move. ]
;W[ec]
C[White must keep Black confined to the corner, so she blocks with 2. ]
;B[df];W[ef];B[eg];W[de];B[ce];W[cd];B[bd];W[cc];B[bc];W[db]
C[With the sequence to 12, White settles her stones at the top, but ... ]
;B[bg]
C[... Black gets a large territory on the left when he hanes at 13. White must now do something about her stones in the lower left. <= ]
)
(;B[ec]
C[How the game continued.  

The hane of Black 1 was an overplay. Black's stones were too thin to support such an aggressive move. ]
;W[dc];B[cc];W[db];B[eb];W[cd];B[de];W[cb]
(;B[ef];W[df];B[ce];W[bf]
LB[df:10]
C[After White 10 and 12, Black's stones in the corner were dead. In spite of this loss, however, Black can still deliver a decisive blow. See Problem 31 for the continuation. <= ]
)
(;B[bc]
C[Instead of @, Black should have played 9 here. ]
;W[bb]
C[If White 10, ... ]
;B[bd]
C[... Black could live by turning at 11. <= ]
))
)
(;
GM[1]
SZ[19]
AW[dg][fj][cn][dn][fo]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][fc][dm][em][fp]
LB[fc:4][dg:3][fj:5][cn:1][fp:2][fo:9][dn:7][dm:6][em:8]
C[Problem 28. Black to play.  

Black 6 and 8 are strong counters to the cap of White 5. But how should Black answer to White 9 ? ]
(;B[en]
TE[2]
C[Correct Answer.  

Cutting through with Black 1 ... ]
;W[eo];B[do]
C[... and 3 is severe. ]
;W[ep];B[eq];W[fq]
LB[dq:B][go:A]
C[Because of the ladder at A, White can't cut at B. ]
;B[dq];W[gp];B[cm]
C[Black gets a lot of profit in the corner with the sequence to 9. <= ]
)
(;B[fn]
C[How the game continued.  

Black clamped with 1, hoping to link up with his stones below. ]
;W[eo]
C[But White's stones were quite flexible ... ]
;B[gp];W[go];B[cp];W[ep];B[eq];W[hp];B[hq];W[fl]
C[... Black's stones on the left side became a liability after White 10. This was a success for White. See Problem 36 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][hd][fj][dm][hb][hc][ef][eg][cp][co][md][nc][oc][pm][ql][jc][kd][ld]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fp][pn][fd][cd][ee][gc][ff][dq][pc][nd][ne][gb][mq][qm][ke][le][me]
LB[mq:1][pm:2][qm:3][ql:4]
C[Problem 29. Black to play.  

After Black made a wall at the top in the game in Problem 25, he played at the bottom at 1. White attached with 2, then blocked with 4. How should Black continue ? ]
(;B[pl]
TE[2]
C[Correct Answer.  

Cutting with Black 1 is a strong move. ]
;W[om];B[qk];W[qn];B[rl]
C[With the sequence to 5, Black builds a strong position which combines well with his thick wall at the top. ]
;W[rm]
C[After White ataris with 6, ... ]
;B[ql]
C[... Black connects with 7 and ... ]
;W[po];B[qp];W[on]
LB[po:8]
C[... White must capture with 8 and 10, ... ]
;B[np]
LB[qp:9]
C[... while Black takes profit in the corner with 9 and 11. White's stones still lack eyes, so they are a good target to attack. <= ]
)
(;B[qn]
C[How the game continued.  

Connecting with Black 1 was a solid move. ]
;W[qh]
C[But when White invaded at 2, ... ]
(;B[qf]
LB[od:A]
C[... Black defended with 3, because he needlessly feared White pushing through at A. ]
;W[qj]
C[This gave White the chance to establish a position on the right side by attaching at 4. As it was, White was gradually catching up. <= ]
)
(;B[qj]
LB[qf:@]
C[Instead of @, Black should have made an iron pillar with 3. White would then be in trouble. <= ]
))
)
(;
GM[1]
SZ[19]
AW[dg][ek][cn][dn][ho][hp][hr][jo][ko][mp][ej][qh][ip]
AB[jp][jd][pj][dj][dp][pd][pp][dd][gc][co][fp][go][gn][jn][qm][hn][cd][io][in][fr]
LB[cd:1][qh:2]
TR[ej]
C[Problem 30. Black to play.  

After White played the marked stone in Problem 26, Black took the corner territory in the upper left with 1. White switched to the right side with 2. How can Black take a decisive lead ? ]
(;B[qf]
TE[2]
C[Correct Answer.  

The checking-extension of Black 1 is severe because it robs White of a base to settle her stone. ]
;W[oh];B[oq]
LB[oc:B][mh:A]
C[Next, Black reinforces his lower right corner while threatening to reduce White's territory at the bottom. Since White's two stones in the upper right are weak, she must strengthen them by jumping to A before she can consider invading the top. But Black will then reinforce his position in the upper right corner with B. <= ]
)
(;B[qj]
C[How the game continued.  

Black 1 was not appropriate in this position. It enabled White ... ]
;W[qd];B[qc];W[qe];B[pc];W[of]
C[... to make a base for her stones with the sequence to 6. With three stable positions, White could now think about fighting for territory with an invasion at the top or the 3-3 point in the lower right corner. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][co][dm][ek][ed][ee][dg][cg][gj][gl][fl][em][cb][db][dc][cd][df][bf]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][cp][dn][en][cf][eh][gh][ej][dk][fm][gm][hm][ec][eb][cc][de][ce][ef]
C[Problem 31. Black to play.  

In spite of his loss in the upper left corner in Problem 27, Black is still ahead. Where should he play next ? ]
(;B[bl]
TE[2]
C[Correct Answer.  

The diagonal peep of Black 1 is the vital point. ]
(;W[cm]
C[White has to connect at 2. ]
;B[hl]
C[Black now attacks the white group ... ]
;W[hk];B[ik];W[hi];B[hh];W[ii];B[jg]
C[... with the sequence to 9, building a moyo at the bottom. White's stones are almost dead, but, even if then do manage to somehow live, it will be in gote and Black has already made a vast moyo in more than half the board. <= ]
)
(;W[cl]
C[If White 2, ... ]
;B[ck]
C[... Black will play 3 and ... ]
;W[cm]
C[... White will eventually have to come back and play 4. <= ]
))
(;B[gc]
C[How the game continued.  

Defending the two stones in the upper left with Black 1 was small. ]
;W[hl]
C[The center was important and White immediately started maneuvers there with 2 ... ]
;B[im];W[jk]
LB[fi:A]
C[... and 4. These moves strengthened White's weak stones. White could also aim at A; Black soon found himself in serious trouble. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][fj][cn][dn][fo][eo]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][fc][dm][em][fp][fn]
TR[eo]
C[Problem 32. Black to play.  

After White draws back with the marked stone (White 2 in Problem 28), what is the correct move for Black ? ]
;B[go]
TE[2]
C[Correct Answer.  

Black must block with 1 ... ]
;W[ep]
C[... even though White can cut through with 2 ... ]
;B[eq]
(;W[fq]
C[... and 4. ]
;B[gp];W[dq];B[er];W[dr];B[fr];W[cp]
LB[ei:A]
C[Black must give White the corner with the sequence to 10, but he gets a moyo at the bottom in exchange. Now that Black's stones are strong, he can split the two white stones on the left in two with a move around A. <= ]
)
(;W[gn]
C[Unreasonable for White.  

Cutting on the outside with White 4 is unreasonable. ]
;B[gq];W[ho];B[gp];W[gm]
C[After White extends to 8, ... ]
;B[cm]
C[... Black 9 kills the stones in the corner. ]
;W[dq]
C[If White cuts at 10, ... ]
;B[cq];W[dr];B[bp]
C[... Black plays the sequence to 13. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ef][dg][hd][hb][hf][nc][nd][cn]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][eg][oc][jf][pf][dm][fp]
TR[ef]
C[Problem 33. Black to play.  

How should Black respond to the marked white stone ? ]
(;B[df]
TE[2]
C[Correct Answer.  

Black is strong around here, so he shouldn't be afraid to crosscut with 1. ]
;W[ff]
C[White extends towards her stones at the top with 2 and ... ]
;B[cf]
C[... Black descends to 3. ]
;W[dh]
C[Since the ladder is unfavourable for White, she must extend to 4. ]
;B[fg];W[ei];B[gg];W[gf];B[gi]
C[After Black 9, White finds her three stones on the left under attack. ]
)
(;B[ff]
C[Variation.  

Black could also hane at 1. ]
;W[fg]
C[White ataris with 2 ... ]
;B[eh];W[fe]
C[... and 4, but ... ]
;B[ee]
C[... Black 5 is a double atari. ]
;W[gf]
C[White captures with 6, ... ]
;B[df];W[ff]
LB[df:7]
C[... then connects with 8 in answer to Black 7. ]
;B[cf]
LB[dh:B][ei:A]
C[Black descends to 9 and has secured the territory there. If White A, Black will simply secure the white stone with B. <= ]
)
(;B[cf]
C[How the game continued.  

Black 1 was a bad move. ]
;W[df]
C[It induced White to connect with 2, rendering the lone black stone useless. ]
;B[ce];W[cg]
C[White got a thick position on the outside, ... ]
;B[fb]
C[... while Black took the corner territory. ]
;W[ec]
C[White exchanged 6 ... ]
;B[dc]
C[... for Black 7 to leave some aji behind. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][cl][cn][dn][en][fn][gn][hm][il][fj]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][dm][em][fm][gm][fp][gp][hl][hk][jj]
LB[fd:4][dg:3][fj:5][cn:1][fp:2][gp:14][dn:7][en:9][fn:11][gn:13]
LB[hm:15][il:17][cl:19][dm:6][em:8][fm:10][gm:12][hl:16][hk:18]
C[Problem 34. Black to play.  

In this nine-stone game, Black played the sequence to 18. How should he respond to White 19 ? ]
(;B[ek]
TE[2]
C[Correct Answer.  

Black should play the diagonal move of 1, not only to strengthen his stones but also to isolate the two white ones in the upper left from their allies below. ]
;W[in]
C[White comes back to defend with 2, ... ]
;B[ik]
LB[ci:B][bj:A]
C[... and Black turns at 3, building a huge moyo in the upper left. If White A, Black will calmly give way with B. <= ]
)
(;B[ej]
C[How the game continued.  

Black 1 was a good move, but ... ]
;W[fk]
C[... answering the peep of White 2 ... ]
;B[gl]
LB[fi:A]
C[... with 3 was cowardly. Black should have haned at A instead. ]
;W[dl];B[fi]
C[Now when Black cut at 5, ... ]
;W[ei]
C[... White crosscut with 6 ... ]
;B[gi];W[di]
C[... and the black stones on the left side became separated from their allies above. ]
;B[cj];W[ek]
C[With 10, White took a big piece of territory on the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][gj][cn][dn][en][fm][gm][cm]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][dm][em][fl][fn][gn][fp]
LB[fd:2][cf:1][cn:3][fp:4][gj:5][dm:6][dn:7][em:8][en:9][fn:10]
LB[fm:11][fl:12][gm:13][gn:14][cm:15]
C[Problem 35. Black to play.  

In this variation, White turns with 15. How should Black continue ? Note the high position of White 5. ]
(;B[hm]
TE[2]
C[Correct Answer.  

Even if the ladder doesn't work. Black 1 is the strongest move because, ... ]
;W[gl]
C[... after White escapes with 2, ... ]
;B[gk];W[hl];B[hk]
LB[gk:3]
C[... the ataris of 3 and 5 maximise Black's wall in the center and neutralise the white stone there. ]
;W[il];B[ek]
LB[ik:C][cq:B][bp:A]
C[Next, Black falls back to fix up his shape with 7. The four white stones on the left still do not have two eyes, so White has to play around A. Black answers with B and White's stones are still not secure. Next, Black can attack the five white stones in the center with C and increase the strength of his wall in the center. <= ]
)
(;B[gl]
C[How the game continued.  

Black simply ataried with 1 ... ]
;W[hm]
(;B[hl]
C[... and pushed out with 3. This move is absolutely necessary. ]
(;W[hn]
C[White turned at 4. <= ]
)
(;W[im]
C[If White had extended to 4 here, she would have had more room to maneuver. <= ]
))
(;B[ek]
C[If Black had played 3 here, ... ]
;W[hl]
C[... White would have turned at 4, confining Black's stones to the right side. <= ]
))
)
(;
GM[1]
SZ[19]
AW[dg][fj][cn][dn][fo][gc][gd][fe][eg][fg][dh][fl][ep][eo][hp][ho][go]
AB[jp][jd][pj][dj][dp][pd][pp][dd][jj][fc][dm][em][fp][ec][ef][ei][eh][fh][gh][fn][eq][cp][gp][hq][ip]
TR[fe]
C[Problem 36. Black to play.  

This position was later reached in the game in Problem 28. How should Black respond when White plays the marked stone ? ]
(;B[ce]
TE[2]
C[Correct Answer.  

White's group at the top and the bottom are weak, while Black's positions at the top and bottom are strong, but both of Black's groups need some reinforcement. The diagonal move of 1 strengthens Black's corner while robbing the white stones of their base, so ... ]
;W[gg]
C[... White must move out into the center, ... ]
;B[hh]
C[... inducing Black to move into the center as well. ]
;W[dq]
C[But White must now look after her group at the bottom. She cuts at 4, and ... ]
;B[er];W[dr];B[fq];W[bq];B[cq];W[cr];B[br];W[bs];B[ar];W[aq];B[ds];W[as]
C[... the sequence continues up to White 16. Next, ... ]
;B[br];W[ar];B[es];W[bp];B[cs];W[cm]
C[... the sequence continues up to White 22 and both the black and white groups in the lower left corner are stabilised. ]
;B[if]
C[However, Black ends with sente and he can build a moyo in the right with 23. White's stones in the upper left can eventually live in gote, but Black has taken a big lead. <= ]
)
(;B[mc]
C[How the game continued.  

Black defended the upper right with 1. This was a lukewarm move, ... ]
;W[bd];B[cc];W[bc];B[bb];W[ab];B[cb];W[ce]
C[... since it gave White the chance to expand her position in the upper left with the sequence to 8. Making eyes for this group was now easy. ]
;B[fb]
C[Black ended in gote when he defended at 9. With her group at the top settled, White could concentrate on the problem of her weak stones on the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][fj][cl][cn][dn][en][fn][gn][hm][il][di][ei][fk][dl][ek]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][dm][em][fm][gm][fp][gp][hl][hk][jj][ej][cj][fi][gi][gl]
TR[ek]
C[Problem 37. Black to play.  

This was the position reached in Problem 34. How should Black respond after White turns with the marked stone ? ]
(;B[cm]
TE[2]
C[Correct Answer.  

Black should cut through with 1 ... ]
;W[bm];B[bn]
C[... and 3. ]
;W[bl]
C[Since Black is now threatening to rescue his three stones above, White must connect at 4. Next ... ]
;B[bo]
C[... Black draws back with 5, securing a big profit in the corner. ]
;W[ep]
C[Black has to be careful of the wedge-in of White 6; ... ]
;B[dq]
C[... Black 7 is the best response. ]
;W[in]
C[In the end, White has to go back and defend with 8, ... ]
;B[eq]
C[... while Black secures the bottom with 9. White's stones in the bottom left still have no eyes, so Black can expect to make additional gains by attacking them. <= ]
)
(;B[im]
C[How the game continued.  

By cutting with 1 ... ]
;W[hn];B[jm]
C[... and extending to 3, Black lost his chance for a big gain in the lower left corner. ]
;W[bp]
LB[bl:D][bn:C][bm:B][cm:A]
C[White slid to 4 and now the sequence Black A - White B - Black C no longer works because White connects at D and the black stone at C can be captured. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][gj][cn][dn][en][fm][gm][cm][hm][hn]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][dm][em][fl][fn][gn][fp][gl][hl]
TR[hn]
C[Problem 38. Black to play.  

After White turns with the marked stone (White 4 in Problem 35), what should Black do ? ]
(;B[il]
TE[2]
C[Correct Answer.  

Extending to Black 1 is a powerful move which affects the entire board. ]
;W[gp]
C[White tries to make shape for her stones on the right with 2 ... ]
;B[fo];W[ho]
C[... and 4, ... ]
;B[cp]
C[... while Black settles the corner with 5. White now has two groups in trouble. ]
(;W[jn]
C[If she runs away with 6, ... ]
;B[dk]
C[... Black will defend with 7 and the four white stones will eventually die. <= ]
)
(;W[dk]
LB[jn:A]
TR[hn]
C[On the other hand, if White attaches at 6 and rescues her four stones on the left, the six white stones on the right will die after Black shuts White in with A. Now you can see why White 4 (the marked stone) in the game in Problem 35 was a bad move. <= ]
))
(;B[ho]
C[How the game continued.  

Black defended the bottom with 1 ... ]
;W[io];B[hp]
C[... and 3. ]
;W[il];B[ik];W[jl];B[hk];W[jk]
TR[gj]
C[It didn't matter that the four white stones were short of liberties because the marked white stone suddenly came to life when White haned at 8. <= ]
)
)
(;
GM[1]
SZ[19]
AW[hc][cf][nc]
AB[pj][dj][dp][pd][pp][dd][fd][pf]
LB[nc:1][pf:2][cf:3][fd:4][hc:5]
C[Problem 39. Black to play.  

White attacks the two black stones in the upper left at their weak underbelly with 5. How should Black respond ? ]
(;B[ce]
TE[2]
C[Correct Answer.  

Black should first attach with 1, ... ]
;W[df]
C[... forcing White to stand with 2. ]
;B[ge]
C[If Black next moves out into the center with 3, ... ]
;W[jd]
C[... White's stones at the top need reinforcement, so she defends with 4. ]
;B[dh]
C[Black now attacks with 5 ... ]
;W[eg];B[gj];W[gg];B[ie]
C[... to 9, ... ]
;W[ig]
LB[gg:8][eg:6]
C[... forcing White to move out into the center with 6 to 10. ]
;B[je]
C[Black now leans on the white group at the top with 11 ... ]
;W[kd];B[ke]
C[... and 13, then ... ]
;W[kg];B[ld];W[lc];B[le];W[md];B[ic];W[id];B[hd];W[ib];B[gc];W[hb];B[hh];W[hg];B[kc];W[jc];B[kb]
C[... squeezes it with the sequence to 29. ]
;W[jb];B[oc]
C[When Black plays 31, White's stones at the top have bad aji and her stones in the center are heavy and lack eyes. <= ]
)
(;B[ge]
C[The order of moves.  

Black 1 is a splendid move ... ]
;W[jd]
C[... that requires a white response at the top. ]
;B[ce]
LB[ge:1][df:A]
C[But, with the black stone of 1 in place, White will not play A in response to Black 3. ]
;W[cn]
LB[df:A]
C[Instead, she will approach in the lower left with 4. This is a subtle point, but a strong player never makes a move like A which clearly leads to a bad position. It is better to play elsewhere and wait to see how the situation in the upper left develops. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nd][qf][pm]
AB[pj][dj][dp][pd][pp][dd][jd][jj][np]
LB[pm:1][np:2][qf:3][jd:4][nd:5]
C[Problem 40. Black to play.  

White plays two approach moves with 3 and 5. Against which stone in the upper right should Black attack ? ]
(;B[pf]
TE[2]
C[Correct Answer.  

With two stones already in place, White is stronger on the right side, so, following the principle of attaching to the stronger stone, Black attaches at 1. ]
;W[pg];B[of];W[qe];B[od];W[rc]
C[The joseki to White 6 follows. Next, ... ]
;B[og]
TR[pj]
C[... Black presses his advantage by driving White in the direction of his marked stone, ... ]
;W[ph];B[oh]
LB[pi:B][oi:A]
C[... pinning her against the side and building a vast moyo in the center. If White A, Black will cut at B and he will have the advantage on the right. If White plays elsewhere, Black B will be a thick move. <= ]
)
(;B[nc]
C[How the game continued.  

Taking territory in the corner with Black 1 ... ]
;W[mc];B[oc];W[md];B[pf];W[pg];B[qe];W[of];B[pe];W[rf];B[og];W[ph];B[re]
C[... to 13 was a negative way of playing. You will never get strong by playing defensively in the opening. ]
;W[nf]
C[With 14, White became strong in the center, while Black was confined to the corner, so strategically it was White who made progress in this opening skirmish. As Black, you should never allow your stones to be isolated in the opening maneuvers. See Problem 44 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][ql][ol]
AB[pj][dj][dp][pd][pp][dd][nd][qn]
LB[qf:1][nd:2][ql:3][qn:4][ol:5]
C[Problem 41. Black to play.  

How should Black continue after White jumps to 5 ? ]
(;B[qk]
TE[2]
C[Correct Answer.  

Black should first exchange 1 for ... ]
;W[rl]
C[... White 2, ... ]
;B[on]
LB[pl:A]
C[... then jump to 3, threatening to wedge in at A and take territory on the side. ]
;W[om]
C[White must defend by exchanging 4 ... ]
;B[nn]
C[... for Black 5. ]
;W[nk]
C[She then runs away into the center by taking the vital point of 6, but ... ]
;B[oi]
C[... Black follows her with 7. White's stones below are on the run, so she hasn't time to think about her lone stone above. <= ]
)
(;B[qe]
C[Variation.  

Black might also exchange 1 ... ]
;W[pf]
C[... for White 2, ... ]
;B[nj]
C[... then jump to 3. ]
;W[rj]
C[Since this move let's White slide to 4, it is a bit slack, but ... ]
;B[ml]
LB[qi:B][rh:A][rf:C]
C[... Black can play for central influence with 5. Later, Black can attack the white stones by playing at A. If White B, Black links up at C. <= ]
)
(;B[jc]
C[How the game continued.  

Black switched to the top, taking a big point at 1. The situation on the right remained fluid, but Black had certainly not fallen behind; he only lost a chance to take a decisive lead. ]
;W[fq];B[fp];W[gp];B[fo];W[eq]
C[This pause allowed White establish a position in the lower left. ]
;B[dq];W[or]
C[She then switched to the lower right with 8. The game was becoming complicated. See Problem 45 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[hc][dg][cn][dn][nc]
AB[pj][dj][dp][pd][pp][dd][fd][co][fp][pf]
LB[nc:1][pf:2][cn:3][co:4][dn:5][fp:6][dg:7][fd:8][hc:9]
C[Problem 42. Black to play.  

As in Problem 39, White attacks the weak underbelly of the two black stones with 9. How should Black play in this position ? ]
(;B[fj]
TE[2]
C[Correct Answer.  

Black should keep the white stones separated by jumping to 1. ]
(;W[gm]
C[If White jumps out into the center with 2, ... ]
;B[fg]
C[... Black will cap with 3. After Black 3, White can live in the upper left, but Black will become strong on the outside, so he can invade at the top. <= ]
)
(;W[gg]
C[If White 2 here, ... ]
;B[fn]
C[... Black caps with B. In this case, Black has no need to worry about his two stones in the upper left; they can easily live. <= ]
))
(;B[dl]
C[How the game continued.  

Attacking with Black 1 was an overplay. ]
;W[fn];B[gk];W[hn];B[hp]
LB[gk:3][fn:2][hn:4]
C[The sequence to Black 5 severely pressed White, but her stones escaped into the center with 2 and 4. ]
;W[cd]
C[She then attached at the top with 6 and was able to live easily. All Black managed to accomplish was to split the white groups above and below, leaving White free to create  complications in the upper left. See Problem 46 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][jd][nc][ql]
AB[pj][dj][dp][pd][pp][dd][pf][df][jp][jj]
LB[ql:7][jp:6][jd:5][nc:1][fc:3][df:4][pf:2]
C[Problem 43. Black to play.  

White invades the right side with 7. How should Black deal with this invasion ? ]
(;B[qn]
TE[2]
C[Correct Answer.  

The pincer of Black 1 is the standard move in this kind of position (see Problem 16). ]
(;W[ol]
C[White's stones are without a base, so she must escape into the center with 2. <= ]
)
(;W[rj]
C[If White 2 here, ... ]
;B[pl]
C[... Black will attach at 3 and build influence in the center. <= ]
))
(;B[qj]
C[Variation.  

Playing Black 1 is a bit weak. ]
;W[qc]
C[White might treat her stone in the lower right lightly and invade the upper right corner with 2. ]
;B[pc]
C[After 3, ... ]
;W[pb];B[qd]
C[... it is important that Black takes sente by turning at 5 ... ]
;W[rb];B[rc]
C[... and playing atari with 7. This secures Black a lot of territory in the upper right side and ... ]
;W[qb];B[qn]
C[... he can also secure territory below with 9. See Problem 47 for the continuation of this game. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nd][qf][pm][mc][md][rf][pg][ph][of][ng]
AB[pj][dj][dp][pd][pp][dd][jd][jj][np][nc][oc][pe][pf][qe][re][og]
TR[ng]
C[Problem 44. Black to play.  

How should Black continue after White played the marked stone (White 14 in Problem 40) ? ]
(;B[oh]
TR[jj]

TE[2]
C[Correct Answer.  

Because of the presence of the marked stone, the ladder is in Black's favour, so he should immediately run away with 1. ]
;W[oi];B[nh];W[pi]
LB[oi:2]
C[White plays 2 and 4, establishing a strong position on the right side, but, ... ]
;B[mh]
LB[le:A][ok:B][nh:3]
C[... after Black 3 and 5,  Black dominates the center and he is threatening to attack the white stones at the top with A or split White's position on the right side with B. <= ]
)
(;B[jp]
C[How the game continued.  

Black 1 was a slack move. ]
;W[oh]
C[It enabled White to remove her bad aji by capturing at 2. White now had a thick position radiating throughout the whole board. Allowing White to get such a thick position in the center is a sure recipe for defeat. A priority for White in handicap games is to remove any bad aji as soon as possible. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][ql][ol][eq][fq][gp][po][or][pq][qq][qr][ps]
AB[pj][dj][dp][pd][pp][dd][nd][qn][jc][dq][fp][fo][qo][pr][nr][oq][op]
LB[ps:10][nr:9][qr:8][op:7][qq:6][oq:5][pq:4][qo:3][po:2][pr:1]
C[Problem 45. Black to play.  

The game in Problem 41 continued up to the sequence of White 10. Where should Black play next ? ]
(;B[mq]
TE[2]
C[Correct Answer.  

Black must establish a thick position in the lower right by defending tightly with 1. Black's stones are now nearly impregnable, so, with this strong position as a backup, he can aim at White's weak stones on the lower left.  <= ]
)
(;B[mp]
C[How the game continued.  

Black 1 also strengthened the black stones at the bottom, but it still left them a bit thin. ]
;W[mr]
C[White attacked the base of these stones with 2 and ... ]
;B[mq];W[ns]
(;B[lr];W[nq];B[np];W[kq];B[nr];W[md];B[mc];W[nq];B[lq];W[ko];B[mm];W[ml]
C[... she was able to throw the game into confusion with the sequence to 16. Instead of being a strong and forceful threatening force, the black stones on the lower right now had to fight for life. <= ]
)
(;B[kq]
LB[lr:@]
C[Instead of @, Black should have jumped to 5. ]
;W[nq]
C[After the exchange of White 6 ... ]
;B[np]
C[... for 7, Black has a thick position facing the center and it still poses a serious threat to the three white stones on the left. <= ]
))
)
(;
GM[1]
SZ[19]
AW[hc][dg][cn][dn][nc][fn][hn][cd][bd][de][gc][id][gg]
AB[pj][dj][dp][pd][pp][dd][fd][co][fp][pf][dl][gk][hp][ce][be][fc][hd][he]
LB[cd:1][bd:11][be:4][ce:2][de:3][gg:5][gc:9][fc:10][hd:6][he:8]
LB[id:7]
C[Problem 46. Black to play.  

After White 1 (White 6 in Problem 42), a sharp clash ensued in the upper left corner. How should Black respond to White 11 ? ]
(;B[bg]
TE[2]
C[Correct Answer.  

Black jumps to 1, increasing the liberties of his two stones. ]
(;W[dc];B[ed];W[eb];B[fb];W[bb]
C[White can live in the corner with the sequence to 6, but, ... ]
;B[df];W[ee];B[ef];W[fe];B[gf]
C[... up to 11, Black secures his stones, while White's two stones below are left without a base. <= ]
)
(;W[ch]
LB[bg:1]
C[Variation.  

If White plays 2 in response to 1, ... ]
;B[dc];W[bb];B[cb];W[bc];B[df];W[ee];B[ef];W[fe];B[ff];W[ge];B[gf];W[gd];B[ba]
C[... Black will take the corner with the sequence to 15. Moreover, the three white stones in the center are almost lost. Black has won the game. <= ]
))
(;B[bc]
C[How the game continued.  

Black seemed to be under an illusion that 1 was a tesuji, but ... ]
;W[cc];B[ad];W[dc]
C[... the black stones on the left were dead after White 4 ... ]
;B[ed];W[cf]
C[... and 6. Black 1 in the Correct Answer was the only move. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][jd][nc][ql][mp][nq][qc][pb][qb][re][qp]
AB[pj][dj][dp][pd][pp][dd][pf][df][jp][jj][qj][np][no][pc][ob][oc][nd]
LB[qj:1][qc:2][pc:3][pb:4][ob:5][qb:6][oc:7][re:8][nd:9][nq:10]
LB[np:11][mp:12][no:13][qp:14]
C[Problem 47. Black to play.  

Black answered the marked stone in Problem 43 with 1. White then invaded the corner with 2 and lived in sente with the sequence to 8. Next, White started operations at the bottom with 10. How should Black continue after White attaches at 14 ? ]
(;B[qq]
TE[2]
C[Correct Answer.  

It is not possible to kill the white stones, so Black should confine White in the corner and take as much profit as possible. To this end, Black 1 is the strongest move. ]
;W[pq];B[oq];W[pr];B[qo];W[rp];B[rq]
LB[ro:B][or:A]
C[After 7, the points A and B are miai. That is, if White A, Black plays B, capturing two stones; if White B, Black plays A, again capturing two stones and taking the corner territory. <= ]
)
(;B[pq]
C[How the game continued.  

Descending to Black 1 was lukewarm. ]
;W[qq]
C[White was able to live in the corner with 2 ... ]
;B[qo];W[ro]
C[... and 4. Moreover, the aji of the white stone above has come to life, so this makes the game more difficult for Black. White's stones here were now settled and she took profit in both the upper and lower right corners. See Problem 51 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][qf][nq][ql]
AB[pj][dj][dp][pd][pp][dd][df][nd][jc]
LB[fc:1][df:2][qf:3][nd:4][jc:6][nq:5][ql:7]
C[Problem 48. Black to play.  

How should Black respond to White 7 ? ]
(;B[np]
LB[qn:A]

TE[2]
C[Correct Answer.  

Since White has a stone on the upper right side, it doesn't make sense to attack at A as in Problem 43. ]
;W[mp];B[no];W[oq];B[pq]
C[Instead, Black can make good shape with the attach-and-extend joseki with the sequence to Black 5. ]
;W[qj]
C[If White next attaches at 6, ... ]
;B[kp]
C[... Black will attack the white stones at the bottom with 7 ... ]
;W[mo];B[mn]
C[... and 9, ... ]
;W[lo];B[pn]
C[... then defend his position with 11. ]
;W[pi]
LB[qi:A]
C[White can't neglect 12, since the hane of Black A is too severe to allow. ]
;B[lr]
C[Next, Black attacks White ... ]
;W[mq];B[jn]
(;W[km];B[jm];W[kl];B[jl];W[kk];B[ij]
C[... with the sequence to 21, building a large-scale moyo in the lower left. <= ]
)
(;W[ko]
LB[jn:15]
C[Variation.  

In answer to Black 15, it is unreasonable for White to cut through with 16 ... ]
;B[jo];W[jp]
C[... and 18. ]
;B[ip];W[jq];B[iq];W[jr];B[ir];W[kq];B[js];W[ks];B[is]
C[White lives, but Black can squeeze her with the sequence to 27, building a thick position on the bottom left. ]
;W[kr]
C[Finally, White must defend at 28 in gote, so Black can now switch to the upper left and attack the white stone there. <= ]
))
(;B[qn]
C[How the game continued.  

Black pincered with 1 ... ]
;W[ol]
C[... and White jumped to 2. ]
;B[pr]
C[Defending the corner with 3 was territorially tight, but it didn't solve the problem of the weak black stone on the right side. ]
;W[md]
C[In relation to this, White 4 was a bit troublesome. See Problem 52 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][hc][he][nd]
AB[pj][dj][dp][pd][pp][dd][fd][ff][kc]
LB[nd:7][kc:4][hc:3][he:5][cf:1][fd:2][ff:4]
C[Problem 49. Black to play.  

White 7 aims at both the top and the upper right. How should Black respond ? ]
(;B[ke]
TE[2]
C[Correct Answer.  

Black should jump into the center with 1, attacking the white stones on both the left and the right. ]
;W[hg]
C[White must defend with 2. ]
;B[pf]
C[Black next jumps to 3, defending the right side, ... ]
;W[nf]
C[... and White again must run away with 4. ]
;B[kg]
C[After Black 5, White is left with three weak groups at the top. If the fighting expands, Black's handicap stones on the side will come into play and give him the edge. <= ]
)
(;B[pf]
C[How the game continued.  

Black meekly defended the right side with 1. ]
;W[ke]
C[This enabled White to cap with 2; her stones at the top were now working together effectively. As you can see, jumping out into the center, as in the Correct Answer, is an important move which conforms to the principle of keeping your opponent's stones separated so that they cannot become a strategically cohesive force. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dg][cn][fm][fj][eg]
AB[pj][dj][dp][pd][pp][dd][fd][fp][jq][eh]
LB[dg:1][fd:2][cn:3][fp:4][fm:5][jq:6][fj:7][eh:8][eg:9]
C[Problem 50. Black to play.  

This is a classic handicap go position. How should Black respond to White 9 ? ]
(;B[fi]
TE[2]
C[Correct Answer.  

Attacking with the diagonal move of Black 1 is the way to make good shape. ]
;W[gi]
C[If White hanes with 2, ... ]
;B[fh]
C[... Black plays 3 and the four stones on the left side make a shape knows as 'guzumi' in Japanese. White can no longer prevent Black from escaping into the center. ]
;W[gf]
C[White's two stones in the upper left are in great danger, so they must escape with 4, but, ... ]
;B[gh]
C[... with Black 5, all of White's stones are under attack. <= ]
)
(;B[fh]
C[How the game continued.  

Black extended to 1, but, ... ]
;W[dh]
C[... when White turned at 2, ... ]
;B[ei]
C[... he was forced to defend with 3 and was left with terrible shape. ]
;W[gf]
LB[hh:A]
C[Next, White jumped to 4 and, even  Black had jumped to A, White would have taken the initiative. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][jd][nc][ql][mp][nq][qc][pb][qb][re][qp][qq][ro]
AB[pj][dj][dp][pd][pp][dd][pf][df][jp][jj][qj][np][no][pc][ob][oc][nd][pq][qo]
TR[ro]
C[Problem 51. Black to play.  

How should Black continue after White hanes with the marked stone (White 4 in the game in Problem 47) ? ]
(;B[qr]
TE[2]
C[Correct Answer.  

The hane of Black 1 is severe. ]
(;W[rr]
C[If White blocks at 2, ... ]
;B[rp]
C[... Black can cut with 3 and ... ]
;W[rq];B[rn];W[po];B[qn];W[pr];B[or]
C[... play the sequence to 9. ]
;W[oq]
C[... Note how Black sacrifices the stone at 9, ... ]
;B[op]
C[... squeezing White with 11, ... ]
;W[ps];B[mq]
C[... 13 and ... ]
;W[nr];B[mr]
C[... 15 and confining her to the corner. ]
;W[os];B[lp]
C[With 17, Black captures a stone and dominates the center. <= ]
)
(;W[qn]
C[Variation.  

White might atari at 2, ... ]
;B[po]
(;W[rm]
C[... then make eye shape with 4. ]
;B[rr]
LB[rk:A]
C[However, Black takes the corner with 5. Black's influence at the bottom is thick and he can still threaten the white stones with A. <= ]
)
(;W[rr]
LB[po:3]
C[Variation.  

After Black connects at 3, White could go for the corner with 4 ... ]
;B[rn];W[pr]
C[... and 6. ]
;B[rp];W[qs];B[oq];W[rq];B[so];W[nr];B[or];W[os];B[mq]
C[However, when Black cuts with 15, White is without a good follow-up. Again White is confined to the corner and Black is thick on the outside. IN handicap games, Black should always strive to make thick positions such as this and the one in the correct answer. <= ]
)))
(;B[rn]
C[Variation.  

The two-step hane of Black 1 is also severe,  but ... ]
;W[pr]
C[... White might play a complicated variation with 2 ... ]
;B[or];W[qr]
C[... and 4. ]
;B[po]
C[Black must connect at 5. ]
;W[oq]
C[If White next cuts with 6, ... ]
;B[mq]
C[... Black cuts with 7 and ... ]
;W[lq];B[mr];W[nr];B[lr];W[kq];B[lp];W[kp];B[mo];W[ko];B[hp]
C[... the sequence continues to 17. White's stones at the bottom are without eyes and under attack, while Black has secured territory on the lower right side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][qf][nq][ql][md][ol]
AB[pj][dj][dp][pd][pp][dd][df][nd][jc][pr][qn]
TR[md]
C[Problem 52. Black to play.  

How should Black continue after White attaches with the marked stone (White 4 in the game in Problem 48) ? ]
(;B[ne]
TE[2]
C[Correct Answer.  

Black extends to 1, reaching out to the lone stone on the right. ]
;W[kd]
C[If White tries to escape at the top with 2 ... ]
;B[jd];W[ke];B[je];W[kf]
C[... to 6, ... ]
;B[ig]
C[... Black is satisfied with the influence he gets in the top after jumping to 7. This is a great success for Black, since all of White's stones are unsettled. <= ]
)
(;B[mc]
C[How the game continued.  

Black haned at 1 ... ]
;W[lc]
C[... and White followed with another hane at 2. ]
;B[ld];W[me];B[le];W[nc];B[mb];W[mf];B[nb];W[lf]
C[Up to 10, White built thickness in the center and a moyo began to emerge. ]
;B[je];W[ic];B[kc]
C[With 13, Black got some territory at the top, but it was quite small compared to White's influence in the center. ]
;W[if]
C[White 14 was on the vital point and this move enabled White to expand her influence on an even grander scale. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][cn][hq][nq][dg]
AB[pj][dj][dp][pd][pp][dd][fc][nc][fq][qm]
LB[hq:9][fq:8][cn:7][qf:1][nc:2][nq:3][qm:4][fc:6][dg:5]
C[Problem 53. Black to play.  

How should Black respond to White 9 ? ]
(;B[bp]
TE[2]
C[Correct Answer.  

Defending the corner with Black 1 is big, about 15 points. It also deprives White of a base for her stone in the lower left. ]
;W[dl]
LB[dm:A]
C[Black is threatening to engulf this stone with A, so White extends to 2. ]
;B[fj]
LB[fl:B][fg:C]
C[Next, Black jumps to 3, threatening to cap at either B or C. Jumping out into the center like this is always a good move in handicap games because Black ensures that this stone won't be attacked, he keeps the white stones separated, and he can attack one of the white groups. <= ]
)
(;B[fo]
C[How the game continued.  

Black jumped to 1. This was a slack move ... ]
;W[bp]
C[... because it allowed White to settle her stones on the left by sliding to 2 ... ]
;B[bo];W[co];B[bq];W[cp];B[cq];W[dl]
C[... and playing the sequence to 8. See Problem 57 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dl][em][dn][fq][hq][qf][qm]
AB[pj][dj][dp][pd][pp][dd][en][eo][cq][jq][np][nd]
TR[hq]
C[Problem 54. Black to play.  

White has extended with the marked stone. How should Black continue ? ]
(;B[jo]
TE[2]
C[Correct Answer.  

Jumping to Black 1 is the strongest move. ]
;W[gn]
C[If White lightly jumps to 2, ... ]
;B[fm]
C[... Black will exchange 3 ... ]
;W[fl]
C[... for 4, ... ]
(;B[gp]
C[... then peep at 5. ]
;W[hp];B[ho];W[go];B[hn];W[fp];B[gm];W[dr];B[cr];W[jr];B[kr];W[ir]
C[White can live with the sequence to 16, ... ]
;B[kq]
C[... but she is confined to the bottom and Black is thick on the outside. <= ]
)
(;B[gm]
C[White is thin.  

Black 5 is not good, ... ]
;W[in]
C[... but White is too thin to jump lightly to 6. ]
;B[gl]
C[Black will turn once at 7, ... ]
;W[fk];B[hp]
C[... then attach with 9. ]
;W[gp];B[ho]
LB[hn:B][go:A]
C[After Black 11, the points A and B are miai, so White's stones are trapped. <= ]
))
(;B[io]
C[How the game continued.  

Black attacked White with the knight's move of 1. This was also a strong move, but ... ]
;W[ho]
C[... it led to complications after White attached with 2. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gd][nc][mf][lp][mp][nq][mr][or][pq][qq][qn]
AB[pj][dj][dp][pd][pp][dd][df][pf][qp][op][np][oq][no][mo][lo][jp]
TR[mf]
C[Problem 55. Black to play.  

White has just played the marked stone with the dual intention of building a moyo at the top and reducing the scale of Black's moyo on the right. How should Black respond ? ]
(;B[qj]
TE[2]
C[Correct Answer.  

Black should reinforce his territory on the right with an 'iron pillar' at 1. ]
;W[gf]
C[If White jumps to 2, Black need not worry about White's moyo at the top. ]
(;B[pb]
LB[lc:A]
C[Black can simply defend the corner with 3 and aim to invade the top at A. <= ]
)
(;B[mh]
LB[pb:@]
C[Variation.  

Black 3 is an even stronger move than @. ]
;W[qc]
C[If White invades the corner with 4, ... ]
;B[pc];W[pb];B[qd];W[rb];B[rc]
C[... Black plays the sequence to 9, ending in sente. ]
;W[qb];B[kh]
C[He then jumps to 11 and builds a vast moyo in the center. <= ]
))
(;B[gf]
C[How the game continued.  

Capping with 1 was a good move, too, but ... ]
;W[ph]
C[... it let White start operations on the right with 2. ]
;B[qj]
C[Again, the 'iron pillar' of Black 3 is the key move. ]
;W[nh]
C[If White 4, ... ]
;B[qh]
C[... Black links up with 5. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][od][nc][pc][qc]
AB[pj][dj][dp][pd][pp][dd][jj][kd][qd][oe][pg]
LB[nc:1][kd:2][qf:3][oe:4][qc:5][qd:6][pc:7][pg:8][od:9][me:A]
C[Problem 56. Black to play.  

White punished Black's weak move at 8 by playing 9 (Black 8 at A would have been the strongest move.). How should Black respond ? ]
;B[rd]
TE[2]
C[Correct Answer.  

Securing the side with 1 ... ]
(;W[ne];B[pf]
LB[mc:B][md:A]
C[... and 3 makes Black thick. The white stones are now vulnerable: Black can aim to attack them by peeping with A, then blocking at B. <= ]
)
(;W[pf]
LB[rd:1]
C[Variation.  

After Black 1, White might push up with 2 and ... ]
;B[of];W[qg];B[pe];W[ph];B[og];W[pi];B[oj];W[qj];B[qk];W[rk]
C[... play the sequence to 12, but ... ]
;B[rl]
C[... the two-step hane of 13 is severe. ]
;W[nh];B[rj];W[qi];B[nj];W[ni]
C[Up to 18, White is out into the center, but ... ]
;B[ri]
C[... she is left with two weak groups after Black 19 ... ]
;W[rh];B[md]
C[... and 21. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][cn][hq][nq][fl][dl][cp][co][bp][dg]
AB[pj][dj][dp][pd][pp][dd][fc][nc][fq][qm][fj][bo][bq][cq][fo]
LB[fl:2][fj:1]
C[Problem 57. Black to play.  

After the sequence in the game in Problem 53, Black 1 and White 2 were exchanged. Where should Black play next ? ]
(;B[fg]
TE[2]
C[Correct Answer.  

Black caps at 1 to keep the lone white stone there under control and to prevent it from doing any damage. ]
;W[cd]
C[Before escaping into the center, White first makes shape for her stones with 2 ... ]
;B[cc];W[de];B[ed];W[be]
C[... to 6. ]
;B[bc];W[ff];B[gg]
C[Even if White lives, Black is not unhappy because he has taken the corner and become strong in the center with 9. <= ]
)
(;B[cf]
C[How the game continued.  

Black played 1 to prevent White from making a base. But this cannot be considered a good move ... ]
;W[cg]
LB[ce:A]
C[... because it provoked White to strengthen her stone with 2 (Black A would have been the appropriate move here). Black's two stones on the left side are were now more vulnerable than before. See Problem 61 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dl][em][dn][fq][hq][qf][qm][ho][gn][fl]
AB[pj][dj][dp][pd][pp][dd][en][eo][cq][jq][np][nd][fm][hn][io]
LB[fl:4][fm:3][gn:2][hn:1]
TR[ho]
C[Problem 58. Black to play.  

After White attached with the marked stone (see Problem 54), Black haned with 1, then exchanged 3 for 4. How should Black continue ? ]
(;B[hp]
TE[2]
C[Correct Answer.  

Black should atari with 1. ]
(;W[go]
C[If White connects with 2, ... ]
;B[gp]
C[... Black pushes through with 3. ]
;W[fp]
C[If White 4, ... ]
;B[ip]
LB[gm:B][fo:A]
C[... Black connects at 5 and the points A and B are miai. White has lost her stones at the bottom . <= ]
)
(;W[gp]
LB[hp:1]
C[Variation.  

In response to Black 1, White can resist with 2 ... ]
;B[go];W[fo]
C[... and 4, but ... ]
;B[ho]
LB[gm:B][fn:A]
C[... Black connects with 5 and White's stones are again trapped, since A and B are miai. <= ]
))
(;B[gm]
TR[fl]
C[How the game continued.  

When White haned with the marked stone, Black extended to 1. ]
;W[in]
C[This gave White the chance ... ]
;B[hm];W[ip];B[jo];W[jp];B[kp];W[ko]
C[... to cut through with the sequence to 8 and ... ]
;B[jn];W[lp]
C[... cut off the three black stones at the bottom with 10 ... ]
;B[kq];W[lq]
C[... and 12. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gd][nc][mf][lp][mp][nq][mr][or][pq][qq][qn][ph][rh]
AB[pj][dj][dp][pd][pp][dd][df][pf][qp][op][np][oq][no][mo][lo][jp][qj][gf]
LB[rh:2][qj:1]
TR[ph]
C[Problem 59. Black to play.  

When White played the marked stone in Problem 55, Black defended with the iron pillar of 1. What should he do if White jumps down with 2 ? ]
(;B[og]
TE[2]
C[Correct Answer.  

The diagonal move of Black 1 is severe. ]
;W[oi]
C[White must escape into the center with 2 ... ]
;B[oj];W[ni]
C[... and 4. ]
;B[mg]
C[Black keeps up the pressure by leaning on the white stone above with 5 ... ]
;W[lg];B[mh]
C[... and 7, ... ]
;W[nj]
C[... forcing White to run away with 8 ... ]
;B[nk];W[mk];B[nl];W[lj]
C[... to 12. But these moves induce Black to make a large territory on the lower left. ]
;B[lf]
C[Next, Black cuts at 13. ]
;W[nf]
C[If White extends to 14, ... ]
;B[oh]
C[... Black exchanges 15 ... ]
;W[pi]
C[... for 16, ... ]
;B[kg]
C[... then ataris with 17 ... ]
;W[lh];B[li];W[kh];B[ki]
C[... to 21. ]
;W[jh];B[mi]
C[After Black exchanges 23 ... ]
;W[mj]
C[... for 24, ... ]
;B[kl]
C[... Black casts a net with 25 and the white group on the right is in trouble. <= ]
)
(;B[ng]
LB[og:@]
C[Variation.  

Black could also play the knight's move of 1, but it is not as decisive as the move @ in the Correct Answer. ]
;W[oi];B[nk];W[mi];B[mg];W[lg];B[lf]
C[Still, White is in trouble when Black cuts with 7. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][od][nc][pc][qc][fd][ff][fh][ih][ql][qn][rp][ne][me][le][qe][rf][rd]
AB[pj][dj][dp][pd][pp][dd][jj][kd][qd][oe][pg][df][dh][hf][hd][qq][np][jp][mf][nf][re][rg][pf][pe]
LB[fd:7][ff:9][hf:10][ih:13][fh:11][df:8][dh:12][jp:6][ql:5]
TR[hd]
LB[np:2][qn:1][rp:3][qq:5]
C[Problem 60. Black to play.  

In the game in Problem 56, White made a lot of profit in the upper right corner. Black then extended with the marked stone and the game continued to White 13. Where should Black play next ? ]
(;B[jg]
TE[2]
C[Correct Answer.  

Black might be able to live at the top, but escaping into the center with 1 is better because the four white stones in the upper left will be stranded without a base. ]
(;W[jh]
C[If White blocks with 2, ]
;B[lf]
C[... Black links up with 3. ]
;W[ke]
C[If White 4 next, ... ]
;B[ig]
C[... Black  plays 5. <= ]
)
(;W[lf]
C[If White 2 here, ... ]
;B[jh]
C[... Black pushes out into the center with 3 and the four white stones on the left will come under attack. <= ]
))
(;B[kg]
C[How the game continued.  

Black thought he could escape with 1 as well, but this move was off the mark. ]
;W[lf]
C[White pushed up with 2, ... ]
;B[lg];W[jf]
C[... then jumped to 4; the black stones were now confined to the top and ... ]
;B[je]
C[... had to make eye shape with 5 ... ]
;W[if];B[ie]
C[... and 7. ]
;W[hg]
LB[fb:A]
C[White, on the other hand, managed to link up all of her stones, so these moves must be considered a complete failure for Black. White could still threaten the corner and the black stones at the top by jumping to A. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][cn][hq][nq][fl][dl][cp][co][bp][dg][cg]
AB[pj][dj][dp][pd][pp][dd][fc][nc][fq][qm][fj][bo][bq][cq][fo][cf]
TR[cg]
C[Problem 61. Black to play.  

After White played the marked stone in Problem 57, what was the best way for Black to continue ? ]
(;B[df]
TE[2]
C[Correct Answer.  

It is usually not a good idea to chase stones from behind with a move like Black 1 because it strengthens the opponent, but here it's an emergency measure which stops White from making sabaki. This move also reinforces Black's corner. ]
;W[eg]
C[If White extends to 2, ... ]
;B[hj]
C[... jumping out into the center with Black 3 is good style because it prepares for an attack on White's stones above. ]
;W[hg]
C[Even if White jumps out to 4, Black can concentrate on attacking because his stones above are secure. <= ]
)
(;B[gg]
C[How the game continued.  

Black tried to confine White on a large scale with 1, ... ]
;W[ce]
C[... but White was able to make sabaki by clamping with 2 ... ]
(;B[df];W[bf];B[cd];W[de];B[ef];W[ee]
C[... and playing the sequence to 8. Black's attack failed. <= ]
)
(;B[cd]
C[Black should have played 3 here. ]
;W[bf]
C[If White 4 next, ... ]
;B[bd]
C[... Black 5 would secure the corner. <= ]
))
)
(;
GM[1]
SZ[19]
AW[dl][em][dn][fq][hq][qf][qm][ho][gn][fl][in][ip][jp][ko][lp][lq]
AB[pj][dj][dp][pd][pp][dd][en][eo][cq][jq][np][nd][fm][hn][io][gm][hm][jo][jn][kq][kp]
TR[lq]
C[Problem 62. Black to play.  

How should Black continue after White plays the marked stone (12 in Problem 58) ? ]
;B[lo]
TE[2]
C[Correct Answer.  

Black should cut with 1. ]
;W[kn]
C[After exchanging White 2 ... ]
;B[jm]
C[... for 3, Black is still threatening to capture two white stones in a ladder, so ... ]
;W[ln]
C[... White must turn at 4. ]
(;B[mo]
C[Extending to 5 keeps the game simple. ]
;W[lr]
C[White must descend to 6, ... ]
;B[mm]
C[... enabling Black to set up a squeeze with 7 and ... ]
;W[iq];B[lm]
C[... build massive thickness in the center and ... ]
;W[jr]
C[... ending in sente. White has secured her stones at the bottom with some profit. Her four stones on the left are extremely vulnerable and Black can now use his thickness in the center to attack them. <= ]
)
(;B[lr]
LB[mo:@]
C[How the game continued.  

Instead of @ in the Correct Answer, Black could also hane with 5 here. ]
;W[mr];B[mq];W[mo];B[kr];W[nr];B[mp];W[lo];B[no];W[iq]
C[After White 14, ... ]
;B[mm]
C[... Black again sets up a squeeze with 15, but it's not as simple as it was before. ]
;W[km]
C[White might push out with 16 and ... ]
;B[kl];W[jl]
LB[kl:17]
C[... atari with 18 if Black blocks at 17, so Black will have a hard time confining White to the side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc]
LB[fc:4][hc:3][nc:1][pf:2][qm:6][nq:5][dm:11][cn:9][co:14][dn:10]
LB[en:12][cq:13][dq:15][fq:7][ip:8]
C[Problem 63. Black to play.  

Where should Black play after White 15 ? ]
(;B[bn]
TE[2]
C[Correct Answer.  

The atari from the bottom with Black 1 is the strongest move. ]
;W[cm]
C[White must not connect at 2 (she should make an approach move in the upper left), because her stones will come under severe attack ... ]
;B[bm]
C[... when Black crawls to 3. ]
;W[em];B[fm];W[ek];B[dk];W[el];B[ej];W[gl];B[gm];W[hl];B[hm];W[il];B[gj];W[gk];B[hj]
C[With the sequence to 17, White's stones are eyeless in the center, while Black has built influence in the upper left. <= ]
)
(;B[cm]
LB[cl:B][bn:A]
C[How the game continued.  

Black cut with 1. This was a joseki move, but there was the aji of White A or White B that Black had to worry about. Moreover, the handicap stone on the left side was not working to its full potential as in the Correct Answer. ]
;W[be]
C[Next, White made a low approach with 2 and a fight soon broke out along the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fq][fr][fo][fm][kq][nq][np]
AB[pj][dj][dp][pd][pp][dd][eq][dn][hq][ho][oq][pn][jj]
LB[fm:13][fo:3][fq:1][fr:5][eq:4][dn:6][ho:8][hq:2][kq:7][nq:9]
LB[np:11][oq:10][pn:12]
C[Problem 64. Black to play.  

What should Black do after White jumps to 13 ? ]
(;B[jq]
TE[2]
C[Correct Answer.  

Attaching with 21 gives the black stones breathing room. ]
;W[ep]
C[White must secure her stones on the left with 2, but ... ]
;B[eo]
C[... after exchanging 3 ... ]
;W[fp]
C[... for 4, ... ]
;B[kp]
C[... Black gets to play another move on the bottom with 5. ]
;W[dq]
C[Next, White makes eye shape with 6 ... ]
;B[cq];W[dr]
C[... and 8, ... ]
;B[cp];W[lq]
C[... then defends her stones on the right with 10. ]
;B[jo]
C[When Black plays 11, all of his stones are secure, but the white stones on the right are still vulnerable. <= ]
)
(;B[fp]
C[Variation.  

Black could have wedged in with 1 and ... ]
;W[gp];B[ep];W[hp];B[go];W[ip];B[fn]
LB[er:A]
C[... cut off the two white stones above with the sequence to 7. Black gets a thick wall on the left, but White's stones at the bottom are secure. Later, the point A is Black's privilege. <= ]
)
(;B[el]
C[How the game continued.  

Black expanded his territory along the left side with 1 ... ]
;W[fl];B[ek]
C[... and 3, but ... ]
;W[ip]
C[... after peeping with 4 and ... ]
;B[hp];W[eo]
LB[fp:A]
C[... playing forcing moves with 6 (note that this move eliminated the aji of Black A) ... ]
;B[do];W[em]
C[... and 8, ]
;B[dm];W[im]
C[... White staked out a big moyo with 10. See Problem 68 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][cf][bd][hc][ge]
AB[pj][dj][dp][pd][pp][dd][pf][fd][cc][kd]
LB[ge:9][kd:8][nc:1][pf:2][cf:3][fd:4][bd:5][cc:6][hc:7]
C[Problem 65. Black to play.  

How should Black answer White 9 ? ]
(;B[ff]
TE[2]
C[Correct Answer.  

Jumping out to Black 1 makes good shape. ]
;W[dh]
C[If White defends the left side with 2, ... ]
;B[fh]
C[... Black will jump to 3. ]
;W[fe]
C[Black need not worry about White cutting through with 4 ... ]
;B[ee];W[ef]
C[... and 6. ]
;B[df]
C[Black will atari with 7, ... ]
;W[eg];B[gd];W[hd];B[he];W[gf];B[fg];W[hf];B[ie]
C[... then power his way through White's position with the sequence to 15. ]
;W[if];B[id];W[dg];B[ic]
C[Up to 19, Black has taken a big profit at the top and dominates the center. <= ]
)
(;B[df]
C[How the game continued.  

Black attached with 1 ... ]
;W[dg];B[ef]
C[... and extended to 3. ]
;W[ch];B[bc]
LB[ch:4][dg:2]
C[He then secured the corner with 5. White also secured her stones with 2 and 4 in sente, so this result was less satisfactory for Black. See Problem 69 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ce][cf][dg][ch][dm]
AB[pj][dj][dp][pd][pp][dd][cd][df][ef][fp]
LB[dm:1][fp:2][cf:3][df:4][dg:5][ef:6][ce:7][cd:8][ch:9]
C[Problem 66. Black to play.  

How should Black answer White 9 ? ]
(;B[fd]
TE[2]
C[Correct Answer.  

Black 1 is a thick move which aims to attack the white stones on the left. ]
;W[fh]
C[White must run away with 2. See Problem 70 for the continuation. <= ]
)
(;B[jc]
C[Variation.  

Taking the big point at the top with 1 is also good. ]
;W[de]
C[Black need not worry about White pushing through with 2 ... ]
;B[ed];W[ee];B[fd];W[fe]
C[... to 6 ... ]
;B[gd]
C[... because he will take the territory at the top with the sequence to 7. The two stones White gains are not enough compensation for the profit Black gains at the top. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][cm][bd]
LB[ed:2][bd:1]
C[Problem 67. Black to play.  

The game in Problem 63 continued with Black defending the corner with 1 and White attaching at 2. What should Black do now ? ]
(;B[ee]
TE[2]
C[Correct Answer.  

Black has the choice of taking the corner or building a wall. Since he is rather thick below, he prefers to have a wall facing towards the bottom, so he will hane on top with 1. ]
;W[dc]
C[White next plays 2 ... ]
;B[cd];W[ec]
C[... and 4 and, ... ]
;B[fd];W[fb];B[gb];W[eb];B[gc];W[bb];B[df];W[bc]
LB[ab:A]
C[... up to 12, she is alive, but confined to the corner. Note, that if White omits this move, Black A kills the corner. ]
;B[hd]
C[Black has made a thick wall facing down the left side and across the top. This is a great success for Black.  <= ]
)
(;B[ce]
C[How the game continued.  

Black actually did make a wall facing down the left side with 1 ... ]
;W[ec];B[dc];W[eb];B[ee];W[fd];B[fe];W[db]
(;B[cb]
LB[db:8]
C[... and he got the corner territory, too, but his wall was not as thick as in the Correct Answer because White established a position at the top with the sequence to 8 and ... ]
;W[df]
C[... somewhat nullified the influence of Black's wall with 10 ... ]
;B[de];W[dh]
C[... and 12. See Problem 71 for the continuation. <= ]
)
(;B[he]
C[Black should have played 9 here to increase the breadth of his moyo. <= ]
))
)
(;
GM[1]
SZ[19]
AW[fq][fr][fo][fm][kq][nq][np][fl][em][eo][ip][im][kn]
AB[pj][dj][dp][pd][pp][dd][eq][dn][hq][ho][oq][pn][jj][do][dm][ek][el][hp][io]
LB[io:1][kn:2]
C[Problem 68. Black to play.  

After White 10 in Problem 64, Black turned at 1 and White blocked at 2. What should Black do about his four stones now trapped at the bottom ? ]
;B[hm]
TE[2]
C[Correct Answer.  

Black has pretty much lost his four stones at the bottom, but the White stones confining them from above are a bit thin, so, if he attaches with 1 ... ]
;W[hl];B[il]
C[... and cuts at 3, he should be able to get some compensation. ]
;W[jm]
C[White must draw back with 4 and ... ]
;B[gl]
C[... Black ataris with 5. ]
(;W[hn];B[hk];W[in];B[fk]
LB[gn:A]
C[With the sequence to 9, Black has made a thick wall on the outside. Even though the four black stones at the bottom are almost captured, there is still some aji remaining at A that could come to life later in the game. <= ]
)
(;W[hk]
LB[gl:5]
C[Unreasonable.  

In answer to Black 5, it is unreasonable for White to extend to 6 here. ]
;B[gm]
C[Black will connect at 7 and ... ]
;W[gk];B[fk]
C[... a capturing race materialises after Black cuts at 9. Black has more liberties and, even if White can create some aji in the corner, the worst Black can get is a seki. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][cf][bd][hc][ge][dg][ch][fh][cn][dn]
AB[pj][dj][dp][pd][pp][dd][pf][fd][cc][kd][df][ef][bc][co][fp]
TR[fh]
C[Problem 69. Black to play.  

Later in the game in Problem 65, White jumped out into the center with the marked stone. Where should Black play next ? ]
(;B[fj]
TE[2]
C[Correct Answer.  

Black jumps out into the center with 1 to relieve the pressure on his stone on the left while putting pressure on the white stones below. ]
;W[fn]
C[If White jumps to 2, ... ]
;B[ci]
C[... Black will attach with 3 to keep White restricted to the upper left and ensuing that  the three white stones below are isolated. ]
;W[bi]
C[Since White hasn't got eyes yet, ... ]
;B[bj];W[di];B[cj];W[gg]
C[... she links up with 8. ]
;B[hj]
C[Finally, Black jumps to 9 and dominates the center.  <= ]
)
(;B[dl]
C[How the game continued.  

Black directly attacked the two white stones with 1, denying them a base. ]
;W[fn];B[gl];W[hn]
C[But this move enabled White to get ahead Black in the race toward the center. ]
;B[hp]
C[After Black defended with 5, ... ]
;W[il]
C[... White turned the tables on Black by attacking his three stones on the left with the cap of 6.  <= ]
)
)
(;
GM[1]
SZ[19]
AW[ce][cf][dg][ch][dm][ic]
AB[pj][dj][dp][pd][pp][dd][cd][df][ef][fp][fd]
TR[ic]
C[Problem 70. Black to play.  

In the game in Problem 66, White played the marked stone, threatening the not-so-weak underbelly of Black's position in the top left. How should Black respond ? ]
;B[kc]
TE[2]
C[Correct Answer.  

Black's position in the upper left is strong, so, following the principle of using thickness to attack, Black should press White against it with 1. ]
;W[ie]
C[White must run away with 2, but ... ]
;B[fj]
C[... Black jumps to 3, putting pressure on the four white stones in the upper left as well as on the one in the lower left. ]
;W[fh]
C[When White runs away with 4, ... ]
;B[ci]
C[... Black attacks with 5 to keep the White group isolated from its ally below. ]
;W[bi];B[bj];W[di];B[cj];W[hh]
C[Finally, when White jumps into the center with 10, ... ]
;B[co]
C[... Black plays 11, securing the lower left sector of the board. ]
;W[fb]
C[Black's corner is secure.  

Some of our readers might be worried about the safety of the black stones in the upper left. However, Black is quite thick and there is little that White can do. White's best chance is to slide to 1. ]
;B[ec];W[eb];B[db];W[cb];B[da];W[cc]
C[When White plays 18, it looks as if she has succeeded in taking the corner. ]
;B[bb]
C[But Black has the brilliant tesuji of 19 which captures the two white stones in the corner. ]
(;W[bc]
C[If White 20 next, ... ]
;B[bd]
C[... Black plays 21. <= ]
)
(;W[bd]
C[If White 20 here, ... ]
;B[bc]
C[... Black plays 21. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][cm][bd][ce][de][ee][fe][dc][cb]
TR[dh]
C[Problem 71. Black to play.  

White has just played the marked stone (12 in Problem 67). How should Black respond ? ]
(;B[ci]
TE[2]
C[Correct Answer.  

Black 1 secures the lower left side and eliminates the bad aji there. It also deprives the three white stones in the upper left of a base, ... ]
(;W[gh]
C[... so White must escape into the center with 2. ]
;B[bg]
C[Next, Black slides to 3 and White no longer has any counterplay on the left side. It should now be an easy game for Black. <= ]
)
(;W[ch]
C[If White 2 here, ... ]
;B[fh]
C[... Black caps with 3. <= ]
))
(;B[kd]
C[How the game continued.  

Black invaded the top with 2, ... ]
;W[pc]
C[... so White settled her stones in the upper right ... ]
;B[qc];W[qb];B[qd];W[ob]
C[... with the sequence to 6. ]
;B[he]
C[The black stone at the top was now vulnerable, so Black reached out to it with 7, a move which also affected the white stones in the upper left. ]
;W[cj]
C[White switched to the left side with 8 and ... ]
(;B[ck];W[cl]
TR[cn][dm]
C[... the aji of the marked stones came to life when White ataried with 10. See Problem 75 for the continuation. <= ]
)
(;B[dk]
LB[ck:@]
C[Black 9 here, building a thick wall towards the center, would have been better than @. <= ]
))
)
(;
GM[1]
SZ[19]
AW[pm][lq][fq][dq][cr]
AB[pj][dj][dp][pd][pp][dd][np][dn][cq][ip]
LB[pm:1][np:2][fq:3][dn:4][lq:5][ip:6][dq:7][cq:8][cr:9]
C[Problem 72. Black to play.  

Black must decide which joseki to play after White hanes with 9. ]
(;B[eq]
TE[2]
C[Correct Answer.  

Black should atari with 1 ... ]
;W[dr];B[er]
C[... and push through with 3. ]
;W[ep]
C[White cuts at 4 and ... ]
;B[fr];W[fp];B[gq];W[gp];B[hq];W[do];B[cp];W[co];B[bo];W[cn];B[bn];W[cm];B[br]
LB[eo:A]
TR[ip][dj]
C[... the sequence to Black 17 is inevitable. Black gets more than 20 points of sure profit. On the other hand, the influence White gets on the outside is neutralised by Black's marked stones and the possibility of Black cutting at A leaves White with bad aji. <= ]
)
(;B[cp]
C[How the game continued.  

The connection of Black 1 was also joseki, but ... ]
;W[er]
C[... when White played 2 her stones in the lower left hat abundant eye-making potential. ]
(;B[ep]
C[Black's lone stone at the bottom was gradually getting weaker and exchanging Black 3 ... ]
;W[eq]
C[... for White 4 didn't help. See Problem 76 for the continuation. <= ]
)
(;B[lo]
LB[ep:@]
C[Instead of @, Black should have played ... ]
;W[ir];B[qo]
C[... the sequence to Black 5 here. <= ]
))
)
(;
GM[1]
SZ[19]
AW[nc][dm][cf][hc][cd][bc][de][be][ch]
AB[pj][dj][dp][pd][pp][dd][pf][fp][fd][dg][cc][bb][ed][ac]
LB[nc:1][pf:2][dm:3][fp:4][cf:5][fd:6][hc:7][dg:8][cd:9][cc:10]
LB[bc:11][bb:12][de:13][ed:14][be:15][ac:16][ch:17]
C[Problem 73. Black to play.  

When Black ataris with 16, White doesn't connect but jumps lightly to 17. How should Black respond ? ]
(;B[kc]
TE[2]
C[Correct Answer.  

Black is strong on the left and the right, so he should make a deep invasion at 1, separating the weak white stones at the top. ]
;W[he]
C[If White jumps to 2, ... ]
;B[oc]
C[... Black exchanged 3 ... ]
;W[nd]
C[... for 4, ... ]
;B[ke]
C[... then jumps to 5. White has now weak groups on the left and the right. It will be difficult for her to save both of them. Black has a won game. <= ]
)
(;B[kd]
C[How the game continued.  

Black 1 was also an invasion, but it lacked the severity of the one in the Correct Answer. ]
;W[kb]
LB[kd:1]
C[White slid to 2 and her stones on the left and the right were able to link up.  

Black 1 was a light move, and such moves are played when it is important to escape quickly. It would be appropriate if White hat had strong positions at the top. However, White was weak and Black was strong. Since Black had nothing to fear, the high invasion of Black 1 was inappropriate. See Problem 77 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pg][nq][pn][om][pl]
AB[pj][dj][dp][pd][pp][dd][jj][mc][jq][on][oo]
LB[pg:1][mc:2][nq:3][jq:4][pn:5][on:6][om:7][oo:8][pl:9]
C[Problem 74. Black to play.  

How should Black respond when White makes the diagonal connection of 9 ? ]
(;B[qq]
TE[2]
C[Correct Answer.  

Black should anchor his three stones in the corner with 1. This move deprives White of a counterplay and leaves the three white stones on the right side and the one at the bottom weak. ]
;W[kp]
C[White might try to escape with 2 ... ]
;B[jp];W[ko]
C[... and 4, but ... ]
;B[jo]
LB[jp:3]
C[... Black keeps White hemmed in with 3 and 5. ]
;W[kn]
C[When White extends to 6, ... ]
;B[mr]
C[... Black slides to 7, ... ]
;W[mp]
C[... forcing White to defend at 8. ]
;B[nm]
C[Next, Black leans on the white group on the right with 9 ... ]
;W[nl];B[ml];W[mm];B[nn];W[nk];B[mk]
C[... to 15. ]
;W[nj]
C[After White extends to 16, ... ]
;B[im]
C[... Black jumps to 17 and the white group at the bottom right is almost dead. <= ]
)
(;B[mp]
C[How the game continued.  

Black attacked the white stones at the bottom with 1, but ... ]
;W[qq]
C[... White invaded the corner with 2. ]
;B[qp]
C[After Black 3, ... ]
;W[pq]
LB[np:A]
C[... White lived with 4. Next, White was threatening to attack with A. Since Black's stones to the right were not secure, Black had a hard time making territory. See Problem 78 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh][cl][cj][pc][ob][qb]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][cm][bd][ce][de][ee][fe][dc][cb][ck][qc][qd][kd]
TR[cl]
C[Problem 75. Black to play.  

White has just played the marked stone (12 in Problem 67). How should Black respond ? ]
(;B[bn]
TE[2]
C[Correct Answer.  

Capturing with Black 1 is the only move. ]
;W[dk]
C[White will atari with 2 and ... ]
;B[bk]
(;W[bl];B[ek];W[dl];B[ci]
(;W[bj];B[bi];W[ak];B[di]
C[... the sequence to Black 11 is one variation. ]
;W[fm];B[go]
LB[fm:12]
C[Next, White and Black escape into the center with 12 and 13. This result is a success for Black, since he has swallowed up the white stones in the upper left. <= ]
)
(;W[di]
C[If White 8 here, ... ]
;B[ej];W[bj];B[bi];W[ak];B[bg]
C[... Black will play the sequence to 13. <= ]
))
(;W[ej]
C[White 4 here would be better. <= ]
))
(;B[ci]
C[How the game continued.  

Black captured a stone with 1 ... ]
;W[bm];B[bj]
C[... and 3, but ... ]
;W[bo]
LB[bm:2]
C[... White also captured one with 2 and then linked up with 4, taking profit in the lower left and leaving Black's stones unsettled, ... ]
;B[go]
C[... so Black ran away with 5. The three white stones above were weakened by Black's ponnuki, but they still have more potential to escape than in the Correct Answer. See Problem 79 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pm][lq][fq][dq][cr][er][fp][fn][qh][oh][pf][rf][nc]
AB[pj][dj][dp][pd][pp][dd][np][dn][cq][ip][cp][ep][nm][nj][qf][qe][re][pb]
LB[nm:1][qh:2][qf:3][nc:4][pb:5][oh:6][nj:7][rf:8][re:9][pf:10]
LB[qe:11][fn:12]
C[Problem 76. Black to play.  

The game in Problem 72 continued with the sequence to White 12. What should Black do next ? ]
(;B[kp]
TE[2]
C[Correct Answer.  

Black's stone at the bottom is weak, so he must strengthen it. But simply running away into the center would please White. Black 1 kills two birds with one stone; it attacks the white stone and it strengthens Black's stone at the bottom. ]
;W[lp]
C[White can't fight. After she pushes up with 2, ... ]
;B[lo]
(;W[jr]
C[... she must slide to 4 and ... ]
;B[ko];W[hq]
C[... ensure a link-up with 6. With the thickness Black makes in the center, he is satisfied with this result. See Problem 80 for an example of how White would continue if Black played as in this Correct Answer. <= ]
)
(;W[mo]
C[If White 4 here, ... ]
;B[mp]
C[... Black cuts at 5, then, ... ]
;W[ko]
C[... if White 5, ... ]
;B[ln]
C[... he extends to 7 and White has no way to defend her stones at the bottom. <= ]
))
(;B[dl]
C[How the game continued.  

Black settled the left side with 1, but ... ]
;W[lo]
LB[in:B][nn:A]
C[... White jumped to 2, threatening to play either A or B. ]
;B[in]
C[Black next jumped to 3, but his future prospects were unclear. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][dm][cf][hc][cd][bc][de][be][ch][kb]
AB[pj][dj][dp][pd][pp][dd][pf][fp][fd][dg][cc][bb][ed][ac][kd]
TR[kd][kb]
C[Problem 77. Black to play.  

After the exchange of the marked black and white stones (Black 1 - White 2 in Problem 73), where should Black play ? ]
(;B[ei]
TE[2]
C[Correct Answer.  

Black 1 is a thick move which defends the marked stone and attacks the white stones above and below. ]
;W[gm]
LB[ff:C][ef:B][ad:A]
C[Jumping to White 2 next is the best move. The white stones in the upper left are quite resilient since White can start a ko at A. If White escapes into the center with B, Black will attach at C and he'll get a thick wall in the center. <= ]
)
(;B[ef]
C[How the game continued.  

Black played the diagonal move of 1, but ... ]
;W[cj]
C[... this allowed White to attach with 2, ... ]
;B[ck];W[dk]
LB[ei:A]
C[... then cut with 4, throwing the left side into a free-for-all fight. Playing 1 in the Correct Answer (A here) prevents White from making sabaki on the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pg][nq][pn][om][pl][lj][mm][pq][qq]
AB[pj][dj][dp][pd][pp][dd][jj][mc][jq][on][oo][nj][mk][mp][qp]
LB[nj:1][lj:2][mk:3][mm:4]
C[Problem 78. Black to play.  

The game in Problem 74 continued with the sequence to White 4. How should Black respond ? ]
(;B[mq]
TE[2]
C[Correct Answer.  

Black's stones in the lower right are a bit thin, but Black can attack White and thicken his stones by blocking at 1. ]
;W[np]
LB[or:A]
C[White must defend against the peep of Black A, ... ]
;B[no];W[mr];B[lr]
(;W[nr]
C[... so he plays the sequence to White 6. ]
;B[mn];W[lm];B[lk]
C[The sequence continues to Black 9 and White has a hard fight ahead of her in trying to save her group in the lower right. <= ]
)
(;W[mo]
C[If White cuts at 6, ... ]
;B[nr]
C[... Black will cut at 7.) <= ]
))
(;B[lk]
C[How the game continued.  

Black defended his stones in the middle with 1, but this left the black stones below unsettled. ]
;W[ln]
C[White attacked with 2 ... ]
;B[lo]
C[See Problem 82 for the way Black should have answered White 2. ]
;W[ko]
C[... and 4, ... ]
;B[lp];W[lr]
C[... then defended by sliding to 6. ]
;B[kq];W[ip]
C[After White 8, the nine black stones were just a long thin string, without any eye-making potential. ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh][cl][pc][ob][qb][bm][bo][gh][ph]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][bd][ce][de][ee][fe][dc][cb][ck][qc][qd][kd][ci][bj][go][cg][he]
LB[cg:2][gh:1][ph:3]
C[Problem 79. Black to play.  

The game in Problem 75 continued with the exchange of White 1 for  Black 2. White then invaded the right side with 3. How should Black respond ? ]
(;B[og]
TE[2]
C[Correct Answer.  

Black should go on the attack with 1 ... ]
;W[oh];B[nh]
C[... and 3. ]
;W[oi]
LB[oh:2]
C[White must escape with 2 and 4. ]
;B[ng]
C[Black connects at 5 (the aggressive Black 5 at A is also possible, but it could lead to complications), ... ]
;W[oj];B[pk];W[ok];B[ol];W[nl];B[om];W[lj]
C[... White makes shape with the sequence to 12, but, in doing so, she helps Black secure territory on the lower right. ]
;B[ih]
C[Black now caps with 13, attacking the white stones on the left and the ones on the right. ]
;W[lh]
C[After exchanging 14 ... ]
;B[me]
LB[pq:B]
C[... for Black 15, White still has to escape with her stones on the right, so Black will be able to take a huge territory on the left. Finally, Black should aim to enclose the lower right corner with B. <= ]
)
(;B[lq]
C[How the game continued.  

The pincer of Black 1 was an interesting idea, but ... ]
;W[pq];B[qq];W[qp];B[qo];W[rp];B[oq];W[pr];B[po];W[qr]
TR[nq]
C[... it enabled White to live in the corner with the sequence to 10. Moreover, the marked stone still had some aji remaining. See Problem 83 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pm][lq][fq][dq][cr][er][fp][fn][qh][oh][pf][rf][nc][lp][jr][hq][cf][fc][gd][cc][cd][ic][ne]
AB[pj][dj][dp][pd][pp][dd][np][dn][cq][ip][cp][ep][nm][nj][qf][qe][re][pb][qj][kp][ko][lo][cj][fd][fe][ec][gc][fb]
LB[cf:1][cj:2][fc:3][fd:4][gd:5][fe:6][cc:7][ec:8][cd:9]
TR[qj]
LB[gc:10][ic:11][fb:12][ne:13]
C[Problem 80. Black to play.  

After Black played the marked stone (Black 7 in the Correct Answer of Problem 76), the sequence to White 13 was played. Where should Black play next ? ]
(;B[qp]
TE[2]
C[Correct Answer.  

Black 1 is the biggest move. Once Black plays here, his territories on the left and right sides and the upper right corner give him an irreversible lead. <= ]
)
(;B[ke]
C[How the game continued.  

With Black's strong position in the top left, Black 1 ... ]
;W[ie];B[kg]
C[... and 3 were forceful moves, but ... ]
;W[kc]
C[... the black stones in the center were a bit vulnerable after White 4. Next ... ]
(;B[ng]
C[... Black attacked with 5, then ... ]
;W[nh];B[mh];W[mi];B[ni];W[mg];B[lh]
C[... played the sequence to 7 to ensure that all his stones could link up. ]
;W[qp]
C[But White attached at 8 and ... ]
;B[qo];W[ro];B[po];W[rp];B[qq];W[rq];B[qr];W[rr];B[mr]
LB[pq:A]
C[(Note that Black 21 was necessary to defend against the cut of White A.) ]
;W[rm]
C[... wiped out Black's potential territory in the lower right by living there with the sequence to 22. ]
)
(;B[qp]
C[Instead of the sequence starting with @, Black should have enclosed the corner simply playing at 5. His two stones at the top were not in that much danger. <= ]
))
)
(;
GM[1]
SZ[19]
AW[dm][cf][bd][ch][cj][dk]
AB[pj][dj][dp][pd][pp][dd][fp][fd][cc][fj][ck]
LB[dm:1][fp:2][cf:3][fd:4][bd:5][cc:6][ch:7][fj:8][cj:9][ck:10]
LB[dk:11]
C[Problem 81. Black to play.  

After Black 10, White crosscuts with 11. How should Black respond ? ]
(;B[ci]
TE[2]
C[Correct Answer.  

The ataris of Black 1 ... ]
;W[bj];B[dl]
C[... and 3 are the strongest moves. ]
;W[ek];B[bi]
C[Black then plays 5, ... ]
;W[bk]
C[... forcing White to defend at 6. ]
;B[cl];W[di];B[ej];W[bh];B[el]
C[The sequence to 11 is now inevitable. White has settled her stones on the left, but Black's thickness in the center is far better than the small profit White has obtained. ]
;W[bl]
C[If White 12, ... ]
;B[cm]
C[... Black will play 13. When faced with a crosscut against your handicap stone on the side, be prepared to give White a small profit and aim to make thickness in the center. <= ]
)
(;B[dl]
C[Variation.  

Black could also play 1 ... ]
;W[ek];B[cm]
C[... and 3. ]
;W[el];B[cl];W[dn];B[bo];W[ej];B[di];W[ci];B[ei];W[fi];B[eh];W[fh];B[eg];W[gj];B[fg]
C[The sequence to 17 is inevitable. Black has secured the lower right corner, while White is left with bad aji in the center. <= ]
)
(;B[ek]
C[How the game continued.  

Black 1 was a bad move. ]
;W[dl];B[ci];W[bj];B[di];W[bi]
C[White was able to link up all of her stones on the left side and take a sizeable territory there as well with the sequence to 6. <= ]
)
)
(;
GM[1]
SZ[19]
AW[pg][nq][pn][om][pl][lj][mm][ln][qq][pq]
AB[pj][dj][dp][pd][pp][dd][jj][mc][jq][on][oo][nj][mk][mp][qp][lk]
TR[ln]
C[Problem 82. Black to play.  

White has just played the marked stone (White 2 in the game in Problem 78). What is the correct way to respond ? ]
;B[mq]
TE[2]
C[Correct Answer.  

Black should block with 1 and force the White stones to live ... ]
;W[np];B[mo];W[mr];B[lr];W[no];B[nn];W[mn];B[rq];W[rr];B[rp];W[nr];B[sr];W[rs]
C[... with the sequence to 14. ]
;B[qm]
C[Although Black's stones in the corner seem to be in danger, ... ]
;W[pm];B[rl];W[qn];B[rn];W[ql];B[rm]
C[... he can easily make eyes up to 21. ]
;W[qj];B[qk];W[pk];B[rk];W[oj];B[pi];W[oi];B[qi];W[nl];B[oh]
C[The sequence continues to 31 with Black taking a big profit on the right, while White's stones in the center are still insecure. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh][cl][pc][ob][qb][bm][bo][gh][ph][pq][pr][qr][qp][rp]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][bd][ce][de][ee][fe][dc][cb][ck][qc][qd][kd][ci][bj][go][cg][he][oq][qq][qo][po][lq]
TR[nq]
C[Problem 83. Black to play.  

The aji of the marked white stone seems to be troublesome. Should Black take countermeasures against it or should he play elsewhere ? ]
(;B[og]
TE[2]
C[Correct Answer.  

The bottom right is small. Black should go after bigger fish and attack the lone stone at the top with the sequence from 1 ... ]
;W[oh];B[nh];W[oi];B[mj]
C[... to 5. White's three stones in the upper right are now in grave danger and will probably be captured. <= ]
)
(;B[or]
C[How the game continued. Black's descent to 1 failed to keep White's stones from linking up. ]
(;W[nr];B[op];W[os]
LB[np:A]
C[After White 4, White was waiting for a chance to attack the black stones in the bottom left by pushing out with A. See Problem 87 for the continuation. <= ]
)
(;W[nh]
LB[or:1]
C[But White should have ignored Black 1 and jumped to 2 instead. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cf][hc][he][bd][ke]
AB[pj][dj][dp][pd][pp][dd][fd][kc][ff][md]
LB[cf:1][fd:2][hc:3][kc:4][he:5][ff:6][ke:7][md:8][bd:9]
C[Problem 84. Black to play.  

White has just slid into the corner with 9. How should Black respond ? ]
;B[cc]
TE[2]
C[Correct Answer.  

Black should play 1, ... ]
;W[dh]
C[... forcing White to defend her stones on the left with 2. ]
(;B[hg]
C[Black then attacks the white stones at the top by playing on the vital point of 3, ... ]
;W[jc];B[jb];W[kb];B[lb];W[kd]
C[... so White has to make shape with the sequence to 8. ]
;B[lc];W[ib];B[gb]
C[Finally, Black can take the territory in the upper left corner with 11 in sente, ... ]
;W[ja];B[qd]
C[... then enclose the upper right corner with 13, to take a substantial lead. <= ]
)
(;B[jc]
C[The vital point.  

Black 3 is another vital point which robs White of her base, but ... ]
;W[hg]
C[... White can jump lightly to 4, putting pressure on Black's stones in the upper left. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qc][qd][qf][kc][ic][nc]
AB[pj][dj][dp][pd][pp][dd][jj][pc][oe][kd][gd][og]
TR[kc]
C[Problem 85. Black to play.  

White attaches with the marked stone, aiming to link up all her stones at the top. What should Black do next ? ]
(;B[jd]
TE[2]
C[Correct Answer.  

Black should extend to 1 and ... ]
;W[jc];B[id];W[hc]
C[... let White link up along the top with the sequence to 4. ]
;B[hd]
LB[ob:B][gc:A]
C[The moyo Black gets in the center after 5 far exceeds the profit White makes at the top. Next, Black A is big, much bigger than the territory White might make by playing White B. <= ]
)
(;B[md]
C[How the game continued.  

Black played 1, expecting White to defend her lone stone in the top right. but ... ]
;W[jd]
C[... White pushed with 2, ... ]
;B[ld];W[gb]
C[... then made a base for her stones by sliding to 4. ]
(;B[cg]
C[Instead of 5, ... <= ]
)
(;B[ec]
C[... Black should have played at 5 here, ... ]
;W[jf]
C[... forcing White 6, ... ]
;B[cg]
C[... then take the corner with 7. This would have been bigger. <= ]
))
)
(;
GM[1]
SZ[19]
AW[jd][nc][ql][qn][dm][ck][cj][ch]
AB[pj][dj][dp][pd][pp][dd][gc][pf][qj][jp][gp][fj][dk]
TR[qn]
C[Problem 86. Black to play.  

White extends with the marked stone to establish a position on the lower right side. How should Black attack these two stones ? ]
(;B[qo]
TE[2]
C[Correct Answer.  

Black should attach with 1 ... ]
;W[pn]
C[... to induce White to defend with 2. ]
;B[np]
C[Black will the defend the bottom with 3. ]
;W[qq]
C[White can't wrest the corner from Black by invading at 4 because ... ]
;B[ro]
LB[ol:A]
C[... Black will answer at 5, after which Black A is too severe for White to allow, so the territory in the corner should become Black's. <= ]
)
(;B[nq]
C[How the game continued.  

Black 1 was a timid move. ]
;W[rp]
C[White slid to 2 and there was no longer an attack on the white stones. ]
;B[qq]
C[Even if Black had answered with 3, White could easily have made eyes for her stones on the lower right, so she could have played elsewhere. White could now fight for what had previously been Black's territory. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh][cl][pc][ob][qb][bm][bo][gh][ph][pq][pr][qr][qp][rp][nr][os][nh][ih]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][bd][ce][de][ee][fe][dc][cb][ck][qc][qd][kd][ci][bj][go][cg][he][oq][qq][qo][po][lq][op][or][gj][ne]
LB[gj:1][nh:2][ne:3][ih:4]
C[Problem 87. Black to play.  

The sequence to White 4 is how the game in Problem 83 continued. What should Black do now ? ]
(;B[kh]
TE[2]
C[Correct Answer.  

Capping with Black 1 should decide the game. It attacks the white stones on the left and on the right. If White somehow manages to live with her stones on the left, Black will use the strength he builds up to attack the two stones on the right. White is bound to lose something. <= ]
)
(;B[lh]
C[Also a good move, but ...  

Black 1 is also a good move, but the scale of the right side is smaller than the left. ]
;W[hj]
LB[lh:1]
C[If White attaches at 2, she has a good chance of settling her stones on the left. In any case, this move (Black 1) is a bit more difficult to handle than the one in the Correct Answer. <= ]
)
(;B[el]
C[How the game continued.  

Black plays 1 to settle his stones in the lower left, but ... ]
;W[lh]
C[... this gave White the chance to defend her stones in the center by jumping to 2. With her stones on the left and the right now linked up, the difference in territory was not that great. White hunkered down for a long fight and saved her stones in the center. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dm][cf][hc][bd][ch][bc][ec][gm]
AB[pj][dj][dp][pd][pp][dd][fp][fd][cc][fj][jq][he][lc]
LB[lc:6][dm:1][fp:2][cf:3][fd:4][hc:5][bd:7][cc:8][ch:9][fj:10]
LB[gm:11][jq:12][bc:13][he:14][ec:15]
C[Problem 88. Black to play.  

After the sequence of White 13 for Black 14, White peeped at 15. How should Black respond ? ]
(;B[fc]
TE[2]
C[Correct Answer.  

The two black stones in the upper left corner are not worth defending, so Black should just block at 1, ... ]
;W[fb];B[ce];W[be];B[gb];W[eb];B[gc];W[ed];B[ee];W[cb];B[eg]
C[... making a thick wall at the top with the sequence to 11. Even if White gets profit in the corner, Black's thickness affects the whole board, and he is sure to get more territory at the top than White does in the corner. <= ]
)
(;B[ed]
C[How the game continued.  

Black defended against the peep by connecting at 1 and White linked up her stones with the sequence to 8. ]
;W[fc];B[ic];W[ib];B[jc]
LB[ic:3]
C[Black 3 and 5 were a tesuji combination to make thickness in the center, but ... ]
;W[hd]
C[... the exchange of White 6 ... ]
;B[ie]
C[... for Black 7 ... ]
;W[cb]
LB[ge:A]
C[... left behind the bad aji of White A. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qc][qd][qf][kc][ic][nc][jd][gb][fq][dq][cq][cn][fn][nq][no][lo]
AB[pj][dj][dp][pd][pp][dd][jj][pc][oe][kd][gd][og][ld][md][cp][eo][em][ip][lq][pn][nm][cg]
LB[nq:1][lq:2][no:3][pn:4][fq:5][nm:6][lo:7][cn:9]
TR[gb][cg]
LB[ip:8][eo:10][cq:11][cp:12][dq:13][em:14][fn:15]
C[Problem 89. Black to play.  

After the exchange of the marked white and black stones (White 4 - Black 5 in the game in Problem 85), the sequence to the peep of 15 was played. How should Black respond ? ]
(;B[fo]
TE[2]
C[Correct Answer.  

Countering the peep by pushing out with 1 shows a positive attitude, refusing to be bullied by White. ]
;W[en];B[dn];W[dm];B[do];W[gn];B[dl];W[cm];B[go];W[hn];B[el];W[ho];B[hp];W[gp];B[eq];W[er];B[gq];W[bp];B[bo];W[co];B[bq];W[fp];B[ap];W[ep];B[bp]
C[With the sequence to 25, Black has secured the left side. ]
;W[gr]
C[Next, White secures her stones in the lower left with 26 and ... ]
;B[ko];W[kn];B[jn];W[jo];B[kp];W[jm];B[ln];W[km];B[mo];W[mn];B[mp]
C[... Black rescues his stones at the bottom with the sequence to 37. ]
(;W[np]
C[If White 38 next, ... ]
;B[mm]
C[... Black ataris at 39. <= ]
)
(;W[mm]
C[If White 38, ... ]
;B[np]
C[... Black links up his stones on the right by pushing through at 39. <= ]
))
(;B[en]
C[How the game continued.  

Black defended against the White peep with 1, ... ]
;W[ep]
(;B[bp]
LB[ep:2]
C[... then descended to 3 against White 2. ]
;W[fo];B[gl]
C[Black played 5 to build a moyo along the left side, but ... ]
;W[in]
C[... after White capped at 6 the two black stones at the bottom had to fight for life. <= ]
)
(;B[fp]
LB[ep:2]
C[How Black should have played.  

After White 2, Black should force with 3, ... ]
;W[eq];B[bp]
C[... then descend to 5. ]
;W[gp];B[fo];W[go];B[in]
LB[gn:B][gm:C][fm:A]
C[Now White can't confine Black to the bottom. After 9, Black threatens to build a moyo with the sequence Black A - White B - Black C. <= ]
))
)
(;
GM[1]
SZ[19]
AW[jd][nc][ql][qn][dm][ck][cj][ch][rp]
AB[pj][dj][dp][pd][pp][dd][gc][pf][qj][jp][gp][fj][dk][nq]
TR[rp]
C[Problem 90. Black to play.  

White has just played the marked stone (White 2 in the game in Problem 86). What should Black do next ? ]
(;B[lc]
TE[2]
C[Correct Answer.  

All of Black's stones are strong, but White's two stones at the top are still weak. Now is the time to attack them by invading at 1. ]
;W[ld];B[kd]
LB[ld:2]
C[Since the ladder is favourable for Black, he will answer White 2 by wedging in with 3. ]
;W[kc];B[ke];W[lb];B[jc];W[kb];B[id];W[le];B[je]
(;W[pb];B[lf]
C[Up to 13, a black moyo in the center has begun to emerge. <= ]
)
(;W[lg]
C[If White 12 here, ... ]
;B[oc]
C[... Black will attach at 13. <= ]
))
(;B[qq]
C[How the game continued.  

Black defended with 1. The territory he got was big, but ... ]
;W[hn]
LB[hp:A]
C[... White got the chance to go on the offensive with 2, aiming to start a fight by attaching at A. If Black defended, White would go after the three stones in the middle. The game was now more difficult that if Black had played the moves in the Correct Answer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][pj][qn]
AB[dp][pd][pp][dd][jj][nd][np]
LB[qf:1][nd:2][qn:3][np:4][pj:5]
C[Problem 91. Black to play.  

White has mapped out a sphere of influence on the right side with the sequence to 5. What should Black do next ? ]
(;B[dj]
TE[2]
C[Correct Answer.  

Black should map out his own sphere of influence on the left side. This works well with Black's handicap stones and Black is well ahead. ]
;W[fq]
C[If White continues with 2 ... ]
;B[dn];W[lq]
C[... and 4 at the bottom, ... ]
;B[jd]
C[... Black will take another big point with 5 at the top. Next, ... ]
;W[fc]
C[... White invades Black's box-shaped moyo with 6 and ... ]
;B[ec];W[fd];B[df];W[hd]
LB[fd:8]
C[... tries to build a base there with 8 and 10. ]
;B[gg];W[hf];B[hg]
C[Black attacks with the sequence to 13, ... ]
;W[jf];B[ld]
C[... then secures the territory at the top with 15. ]
;W[ig];B[hi]
C[After 17, Black's moyo in the upper left is nearly impregnable. White's stones at the top, however, are still not secure. Black has taken a big lead. <= ]
)
(;B[rd]
C[How the game continued.  

Defending the corner with  Black 1 was not urgent and didn't take the whole board into account. Even though White's framework on the right was threatened, ... ]
;W[lq]
C[... White played quickly and established a presence in virgin territory. This is an important principle for White to follow in handicap games: 'If Black plays a lukewarm move, ignore it and play elsewhere.' <= ]
)
)
(;
GM[1]
SZ[19]
AW[nd][qf]
AB[dp][pd][pp][dd][jj][qj]
LB[qf:1][qj:2][nd:3]
C[Problem 92. Black to play.  

White makes two approach moves with 1 and 3 against the black stone in the upper right corner. On which side should Black attach ? ]
(;B[ne]
TE[2]
C[Correct Answer.  

Black should follow the proverb which advises: 'Attach against the stronger stone !' In this case, the white stone on the right is the weaker one because of the presence of the black pincer, so Black attaches with 1. ]
(;W[qc];B[qd];W[pc];B[od];W[oc];B[of]
C[The sequence to 7 is a joseki. ]
;W[md]
C[If White 8 next, ... ]
;B[oj]
C[... Black plays 9. <= ]
)
(;W[me]
C[Variation.  

White can also play 2. ]
;B[oe]
C[After Black draws back with 3, ... ]
;W[qc]
C[... White invades the corner with 4. ]
;B[qd];W[pc];B[od];W[oc];B[mf];W[md];B[ng]
C[The sequence to 11 is a joseki. Just as in the Correct Answer, Black has made a moyo on the right side. <= ]
))
(;B[pf]
C[How the game continued.  

Black attached on the right with 1 and ... ]
;W[pg];B[of];W[qe];B[od];W[rc]
LB[og:B][pj:A]
TR[qj]
C[... the joseki to 6 followed. White settled her stones in the upper right corner and the marked black stone on the right ended up on the wrong point. If this stone were at A, Black 7 at B would then be a powerful move. ]
(;B[ne]
C[As it was, Black 7 was a bad move. <= ]
)
(;B[nc]
C[Black 7 here was the correct way to end this joseki. <= ]
))
)
(;
GM[1]
SZ[19]
AW[mc][qf]
AB[dp][pd][pp][dd][pj]
LB[mc:3][qf:1][pj:2]
C[Problem 93. Black to play.  

This time White's second approach move at 3 is lower and farther away than in Problem 92. How should Black respond ? ]
(;B[qe]
TE[2]
C[Correct Answer.  

Black attaches at 1 and ... ]
(;W[pf]
C[... White's stones on the right become heavy when she stands with 2. ]
;B[nd]
C[Next, Black exchanges 3 ... ]
;W[md]
C[... for 4, ... ]
;B[ne]
C[... then moves out into the center with 5, keeping the two white groups separated. ]
)
(;W[oe]
C[If White 2 here, ... ]
;B[pf];W[pe];B[qd]
C[... the sequence to 5 follows. Black's corner is safe and White's stones are in disarray. <= ]
))
(;B[oe]
C[How the game continued.  

Black played 1, ... ]
;W[qc];B[qd];W[pc]
LB[qc:2]
C[... so White settled her stones at the top with 2 and 4. ]
;B[me]
C[Black jumped to 5, but this move hat little effect on White's stones above, so ... ]
;W[qn]
C[... White switched to the bottom area to erase Black's moyo there. ]
;B[qo];W[pn];B[np];W[rj]
C[White slid to 10, but ... ]
;B[rl]
C[... Black could attack ... ]
;W[ql];B[rk];W[qk];B[qj];W[ri]
C[... with the sequence to 16. ]
;B[rm]
LB[rn:A][qm:B]
C[After 17, A and B were miai. ]
;W[ok]
C[If White 18, ... ]
;B[rn]
C[... Black connects with 19. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][qf][qc][qd]
AB[dp][pd][pp][dd][gc][pc][oe]
LB[gc:2][nc:1][qf:3][oe:4][qc:5][pc:6][qd:7]
C[Problem 94. Black to play.  

Black 2 is unorthodox, but, being played so early in the game, it can't be called a bad move. What should Black do after White crawls to 7 ? ]
;B[og]
LB[qh:C][rg:B][qg:A]

TE[2]
C[Correct Answer.  

Black should jump to 1. White cannot afford to let Black play the sequence Black A - White B - Black C, ... ]
(;W[ph]
C[... so she defends with 2. ]
;B[kd]
C[Next, Black makes a moyo at the top with 3. <= ]
)
(;W[kd]
C[Variation.  

White might play 2 here and take her chances in the corner. ]
;B[qg]
C[When Black attaches at 3, ... ]
;W[pf]
C[... White resists with 4. ]
;B[of]
C[Black must connect at 5. ]
;W[pg];B[ph];W[qh]
LB[pg:6]
C[White can then capture two stones on the right by cutting through with 6 and 8, ... ]
;B[rg];W[pi];B[oh]
(;W[rh];B[qe];W[rf];B[re];W[sg]
C[... then playing the sequence to 16. ]
;B[qb]
C[But Black gets the corner when he hanes at 17. <= ]
)
(;W[rf]
LB[oh:11]
C[When Black connects at 11, White could secure the corner with 12 and ... ]
;B[qi];W[rh]
C[... capture two stones with 14 as well, but ... ]
;B[ri]
C[... she is confined to the side ... ]
;W[sg];B[pj]
C[... and Black's wall radiates influence throughout the board. ]
;W[jp]
C[White 18 seems to block the ladder, but ... ]
;B[md]
C[... Black attacks the top with 19. ]
;W[oi]
C[If White now tries to run away with 20, ... ]
;B[nj]
C[... Black can capture these stones ... ]
;W[ni];B[mi]
C[... in a lose ladder with the sequence to 23. <= ]
))
)
(;
GM[1]
SZ[19]
AW[qf][qn][pj][oo][lo][lq][io]
AB[dp][pd][pp][dd][nd][rd][np][nn][iq][gp]
LB[qf:1][nd:2][qn:3][np:4][pj:5][rd:6][lq:7][iq:8][lo:9][nn:10]
LB[io:11][gp:12][oo:13]
C[Problem 95. Black to play.  

After Black defended the corner with 6 (Black 1 in the game in Problem 91), White switched to the bottom with 7. After Black 12, White peeps with 13. How should Black respond ? ]
;B[po]
TE[2]
C[Correct Answer.  

Black could cut through with 1 ... ]
(;W[pn];B[on]
TR[oo]
C[... and 3. He captures the white stone and makes perfect shape. White's peep with the marked stone in the Problem was an overplay. <= ]
)
(;W[on]
LB[po:1]
C[Variation.  

White might answer Black 1 with 2, ... ]
;B[pn]
(;W[pm]
LB[pn:3]
C[... then block with 4 after Black pushes in with 3. ]
;B[om];W[nm];B[ol];W[no];B[pl]
C[But Black would then secure the right side with the sequence to 9. <= ]
)
(;W[om]
LB[on:2]
C[Variation.  

White could keep pushing out with 2 and 4, ]
;B[pm];W[op];B[oq];W[nq];B[nr];W[mq];B[ol];W[nm];B[nl];W[mm]
C[... then capture two stones with the sequence to 16. However, she ends in gote and her stones are overconcentrated. ]
;B[pq]
C[Black can now use his sente to secure the territory in the lower right corner. <= ]
))
)
(;
GM[1]
SZ[19]
AW[fc][fe][fb][id]
AB[dp][pd][pp][dd][hc][ec][df]
LB[fc:1][df:4][fe:3][ec:6][fb:7][hc:2][id:5]
C[Problem 96. Black to play.  

What should Black do after the exchange of 6 for White 7 ? ]
(;B[ic]
TE[2]
C[Correct Answer.  

Crawling to Black 1 is an important move. It prevents White from making a base at the top. ]
;W[jd];B[hd];W[he];B[jc];W[kd];B[lc]
C[Up to 7, Black gets territory at the top and ... ]
;W[ge]
LB[gd:A]
C[... White must play 8 to defend against Black's peep at A.- ]
;B[ld]
C[Next, Black reinforces his position at the top by pushing out with 9. <= ]
)
(;B[eb]
C[How the game continued.  

Black defended the corner with 1 and ... ]
;W[ic]
C[... White took control of the top with 2. ]
;B[fd];W[gd];B[ed]
LB[fd:3]
C[Black then reinforces his stones with 3 and 5, but ... ]
;W[hd]
LB[gd:4]
C[... this enabled White to also reinforce with 4 and 6, so she got a thick position at the top. ]
;B[dj]
C[Finally, Black mapped out a large territory on the left side with 7. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ec][fc][gd][dg][cn]
AB[dp][pd][pp][dd][fd][fe][dj][fp]
LB[cn:1][fp:2][dg:3][dj:4][fc:5][fd:6][gd:7][fe:8][ec:9][ed:A]
C[Problem 97. Black to play.  

White extends to 9, threatening to push through the gap at A. Should Black be concerned about this ? How should he respond ? ]
;B[dc]
TR[dg]

TE[2]
C[Correct Answer.  

Since the marked stone is two spaces away, Black should block with 1 and ... ]
;W[ed];B[ee];W[de]
LB[ed:2]
C[... let White cut through with 2 and 4. ]
;B[db];W[hc];B[df];W[ce];B[cf];W[be];B[bf]
C[Black then confines White to the corner with the sequence to 11. ]
;W[bc];B[bb]
C[After the exchange of 13 ... ]
(;W[ab]
C[... for White 14, ... ]
;B[eg]
C[... Black makes shape with 15 and builds a moyo on the left side. ]
;W[cb]
C[White can live in the corner with 16, but ... ]
;B[bd]
C[... Black captures three stones with 17. ]
;W[ad]
LB[bd:17]
C[Resistance.  

If White resists with 18 after Black 17 in the Correct Answer, ... ]
;B[cd];W[ae];B[af];W[ac];B[ba];W[ca]
(;B[cc];W[aa];B[ba]
C[... Black captures all the white stones with the sequence to 27. <= ]
)
(;B[da]
C[If Black plays 25 here, ... ]
;W[aa]
C[... he will lose the capturing race. <= ]
))
(;W[ef]
LB[bb:13]
C[Variation.  

If White answers Black 13 by cutting at 14, ... ]
;B[bd];W[cd];B[cc];W[ad]
C[(Note that after White captures with 18, ... ]
;B[af]
C[... Black 19 is best.) ]
;W[ae];B[ab]
C[... Black captures the white stones in the corner with the sequence to 21. ]
;W[ff]
C[The ladder at 22 hit's Black's bottom-right corner stone. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][iq][nq]
AB[dp][pd][pp][dd][jj][fp][pn]
LB[cn:1][fp:2][nq:3][pn:4][iq:5]
C[Problem 98. Black to play.  

White extends to 5, aiming at the weak underbelly of the two black stones at the left. What should Black do ? Note that White 5 is usually played one point to the left. ]
(;B[co]
TE[2]
C[Correct Answer.  

Attaching with 1, ... ]
;W[dn];B[dk]
C[... then pincering with 3, leaves White with a heavy shape on the left. ]
;W[fn]
C[White jumps to 4, ... ]
;B[hp]
C[... but Black makes a shoulder hit with 5. ]
;W[ip]
C[White will push up with 6, but ... ]
;B[ho]
C[... Black extends into the center with 7. Black's stones below are now strong, ... ]
;W[fk]
C[... so White must escape with her three stones on the left by jumping to 8. ]
;B[di]
C[But this induces Black to strengthen his territory on the left side with 9. <= ]
)
(;B[go]
C[How the game continued.  

Since the white stone on the bottom left was two spaces away, the diagonal move of Black 1 didn't put much pressure on it, ... ]
(;W[bp]
C[... so White took the opportunity to settle her stones with 2 ... ]
;B[cq];W[ck]
C[... and 4. ]
;B[kq]
C[Black invaded with 5, but this move was not so severe and ... ]
;W[io]
C[... White jumped out into the center with 6 and all of Black's stones came under pressure. <= ]
)
(;W[dj]
C[White 2 here would also be feasible. ]
))
)
(;
GM[1]
SZ[19]
AW[nc][fc][jd][ch]
AB[dp][pd][pp][dd][df][pf][jq]
LB[jq:6][nc:1][pf:2][fc:3][df:4][jd:5][ch:7]
C[Problem 99. Black to play.  

White attacks the black stones in the upper left with 7. A pincer against this stone is the usual response, but how far away should Black play it ? ]
(;B[ck]
TE[2]
C[Correct Answer.  

Black 1 is the ideal pincer against the white stone. ]
;W[eh];B[ff];W[ek];B[dm]
LB[cj:A][ek:4]
C[The sequence to Black 5 is a joseki. If White omits 4, Black will attack the two white stones above by playing at 4 himself. Timing is important, but if Black plays A later, the three white stones will be without a base, so White wants to play there as soon as possible. See Problem 84. <= ]
)
(;B[eg]
C[How the game continued.  

Black 1 was a lukewarm move. ]
;W[cn]
C[It let White easily settle her stones on the left with 2 ... ]
;B[fp];W[dj]
LB[eg:1]
C[... and 4. This Black 1 had little effect on the white stones on the left and it was also too far away to have much effect on White's stones at the top. This is a good example of how White takes advantage of a slack black move. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ch][cn][iq]
AB[dp][pd][pp][dd][jj][fd][fp]
LB[hq:A][iq:5][fp:2][cn:1][ch:3][fd:4]
C[Problem 100. Black to play.  

White 5 is unorthodox; playing this move at A is more common. How should Black respond ? ]
(;B[mq]
TE[2]
C[Correct Answer.  

Black should keep his distance to avoid inducing White to strengthen her stone at the bottom. Enclosing the corner with Black 1 is just the right distance. ]
;W[fr]
C[If White slides to 2, ... ]
;B[dq]
C[... then 3 is a smart move ... ]
;W[bp];B[bq];W[cp];B[cq]
LB[bq:5][cp:6][bp:4]
C[... because Black can secure a base in the corner with 5 and 7 if White plays 4 and 6. <= ]
)
(;B[kq]
C[Variation.  

The pincer of Black 1 is also possible, but ... ]
;W[io];B[ko];W[fn];B[gq];W[im];B[bp]
LB[bo:B][cl:A]
C[... Black gets confined to the corner with the sequence to 7. Black is threatening to invade at A, so White might try to strengthen her position her by attaching at B. Let's look at one possible continuation after White B. ]
;W[bo]
C[When White attaches with 8, ... ]
;B[fl]
C[... Black 9 is the vital point. ]
;W[bq];B[cp];W[ap]
LB[bq:10]
C[Black lets White get a foothold in the corner with 10 and 12, ... ]
;B[dn]
C[... but then he counterattacks with 13 ... ]
;W[dm];B[en];W[em];B[fm];W[gn];B[cm]
C[... to 19. White's position collapses. As this example shows, when a thick position (Black's in this case) faces a thin one, there is usually the side with the thickness to gain a decisive advantage. <= ]
)
(;B[bp]
C[How the game continued.  

Defending the corner with Black 1 was a lukewarm move ... ]
;W[mp]
C[... because it allows White to establish a base at the bottom with 2. ]
;B[qn];W[fr]
C[Next, White reduces the size of Black's corner by sliding to 4, ... ]
;B[dr]
C[... forcing Black to defend at 5. ]
;W[dl]
C[When White reinforced the left side with 6 she has established stable positions both on the left and the bottom. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][cn][dm][co][cj]
AB[dp][pd][pp][dd][cf][dn][en][cp]
LB[fc:1][cf:2][cn:3][dn:4][dm:5][en:6][co:7][cp:8][cj:9]
C[Problem 101. Black to play.  

White extended to 9. Where should Black play next ? ]
(;B[jq]
TE[2]
C[Correct Answer.  

Black should take the big point at the bottom by extending to 1. ]
(;W[do]
C[You might be afraid of White cutting through with 2 ... ]
;B[eo];W[ep]
C[... and 4, ... ]
;B[bp];W[cm];B[fp];W[eq];B[fq];W[dr];B[fr];W[br];B[dq]
C[... but when Black plays 13 ... ]
;W[er];B[cr]
C[... and 15, White's stones in the corner are dead. <= ]
)
(;W[db]
LB[do:@]
C[Instead of @, White might play ... ]
;B[cc];W[ic]
C[... the sequence to 4 at the top. ]
;B[qj]
C[Black would then take another big point on the right side around 5. <= ]
))
(;B[db]
C[How the game continued.  

Black enclosed the corner with 1, but ... ]
;W[nq]
C[... this let White take the initiative in the lower right with the approach moves of 2 ... ]
(;B[jq];W[qn]
C[... and 4. ]
;B[pn]
C[Next, Black should attach at 5. <= ]
)
(;B[pn]
C[Black should not play at 3 here, ... ]
;W[jq]
C[... because White would take the point 4 and neutralise Black's influence on the left. Don't be afraid of double approaches against your handicap stone. If you are, it will be easy for White to gain the advantage. <= ]
))
)
(;
GM[1]
SZ[19]
AW[qf][fc][fq][lq][qn]
AB[dp][pd][pp][dd][mc][cg][cm][np]
LB[qf:1][mc:2][fc:3][cg:4][fq:5][cm:6][qn:7][np:8][lq:9]
C[Problem 102. Black to play.  

After 9, White's stones are widely spaced, while Black's are tight and strong. What should Black do next ? ]
(;B[pj]
TE[2]
C[Correct Answer.  

Since Black's stones are strong relative to White's, Black should invade the right side with 1 and ... ]
;W[rp];B[qq];W[pl]
LB[qq:3][rp:2]
C[... let White settle her stones with 2 and 4, because Black also settles his stones in the corner by occupying the important 3-3 point with 3. ]
;B[qd]
C[Next, Black defends the top right corner with 5, aiming at the white stone. White is not making any territorial gains: she is only struggling to keep her stones alive. <= ]
)
(;B[dq]
C[How the game continued.  

Black 1 was passive - it ran away from the real scene of battle. ]
;W[oq]
C[White took the opportunity to settle her stones at the bottom ... ]
;B[op];W[pr];B[pk];W[qq];B[qp];W[rp];B[ro];W[rq]
C[... with the sequence to 10, ... ]
;B[qo];W[on];B[pm];W[pn];B[rm]
C[... while Black settled his position on the right side with 15. White ended in sente and her group of three stones still had aji. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][fc][jd][ch][ce][dj][cn]
AB[dp][pd][pp][dd][df][pf][jq][eg][fp][qj]
LB[qj:1][ce:2]
C[Problem 103. Black to play.  

The game in Problem 99 continued with Black 1 followed by the peep of White 2. How should Black respond ? ]
;B[cd]
TE[2]
C[Correct Answer.  

Blocking with Black 1 is best. ]
;W[cf]
C[White draws back with 2. ]
;B[fd]
C[After the sequence from Black 3 ... ]
(;W[ec];B[ed];W[gd];B[ge];W[hd]
C[... to White 8, ... ]
;B[dc]
C[... Black plays 9; he has secured the corner and his stones are out into the center. <= ]
)
(;W[gd]
LB[fd:3]
C[Variation.  

In answer to the attachment of Black 3, White might hane at 4. ]
;B[ec]
C[In that case, Black will block with 5. ]
;W[fe];B[ed];W[gc]
C[After White connects with 8, Black again has secured the corner and is out into the center. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ch][cn][iq][ek][lq]
AB[dp][pd][pp][dd][jj][fd][fp][ck][bp]
LB[ck:1][ek:2]
TR[lq]
C[Problem 104. Black to play.  

Instead of playing as in the game continuation of Problem 100, White played the marked stone and Black invaded with 1. How should he respond to the cap of White 2 ? ]
(;B[dj]
TE[2]
C[Correct Answer.  

Black should move out in the direction from his strong position at the bottom. ]
;W[eh]
C[White will jump to 2 and ... ]
;B[ej]
C[... Black will push up with 3. ]
(;W[gk]
C[If White next jumps to 4, ... ]
;B[fj]
C[... Black will extend to 5 and White is divided into two weak groups. <= ]
)
(;W[fj]
LB[ej:3]
C[After Black 3, White 4 is unreasonable because ... ]
;B[fk]
C[... Black will cut at 5. <= ]
))
(;B[dm]
LB[em:B][cj:A]
C[How the game continued.  

Black 1 was small. Even though Black secured the left side, this stones there became overconcentrated and the territory was not that big. Moreover, White hat forcing moves at A and B, so Black would have a hard time attacking the white stones on the upper left side. ]
;W[qn]
C[But White approached at 2 on the right. The game was now difficult for Black. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][cj][dm][cn][co]
AB[dp][pd][pp][dd][cp][dn][en][fp]
LB[fc:9][fp:8][en:6][dn:2][cp:4][cn:1][dm:3][co:5][cj:7]
C[Problem 105. Black to play.  

After White extended to 7, Black defended tightly with 8. White then approached the black stone at the top with 9. How should Black respond ? ]
(;B[jc]
TE[2]
C[Correct Answer.  

Black should not play in the area of White's strength on the left side. Instead, he should pincer with 1 and ... ]
;W[cf]
C[... wait for White to make a second approach move at 2. ]
;B[df]
C[Since Black is weak, he should attach at 3, making his stones strong. ]
;W[dg];B[ce];W[ef];B[de];W[cg]
C[If White connects at 8, ... ]
;B[db]
C[... Black defends the corner with 9. Black's stones are secure, so ... ]
;W[fe]
C[... he doesn't mind being confined by White 10 - ... ]
;B[nd]
C[... he maps out territory in the top right with 11. <= ]
)
(;B[cg]
C[How the game continued.  

Black 1 was exactly the move White was hoping for. ]
;W[cc]
C[White wrested the corner from Black ... ]
;B[dc];W[cd];B[de];W[ce]
(;B[cf];W[db];B[eb];W[cb]
C[... with the sequence to 10, ... ]
;B[ec];W[fe]
C[... then neutralised Black's thickness by jumping to 12. This was a very bad result for Black. <= ]
)
(;B[cb]
LB[ce:6]
C[Variation.  

After White 6, Black should have haned with 7 ... ]
;W[bb];B[db]
C[... and connected with 9. ]
;W[cf];B[df];W[bg];B[bh];W[ch];B[dg]
C[With the sequence to 15, Black is thick in the center. ]
;W[bi];B[bc]
C[After exchanging 17 ... ]
;W[bd]
C[... for 18, ... ]
;B[hc]
C[... Black can pincer with 19. ]
;W[fe]
C[If White 20, ... ]
;B[he]
C[... Black plays 21. ]
;W[fg]
C[If White then plays 22, ... ]
(;B[fb]
C[... Black can link up his stones by attaching with 23. <= ]
)
(;B[ab]
C[Even if Black's stones get cut off, they can live by starting a ko ... ]
;W[ba];B[bf];W[ag];B[ad]
C[... with the sequence to 27. <= ]
)))
)
(;
GM[1]
SZ[19]
AW[fc][ci][cn][lc][qf]
AB[dp][pd][pp][dd][cf][fp][jq][nd]
LB[lc:9][nd:4][qf:3][jq:6][fp:2][cn:1][ci:5][cf:6][fc:7]
C[Problem 106. Black to play.  

Just as in Problem 102, Black is strong and White is thin after Black 9, so Black should attack. Where is the vital point ? ]
(;B[qj]
TE[2]
C[Correct Answer.  

The pincer of Black 1 attacks the white stone at the top and also stakes out a moyo at the bottom. ]
;W[rd]
C[White must settle her stones with 2 ... ]
;B[qc];W[qh]
LB[qc:3]
C[... and 4, enabling Black to settle his own as well by taking the crucial 3-3 point with 3. ]
;B[oj]
C[Next, Black jumps to 5 and a vast moyo has taken shape in the lower right. <= ]
)
(;B[id]
C[How the game continued.  

Black 1 was the wrong move. ]
;W[le]
C[White jumped to 2, attacking the black stones on the right, ... ]
;B[nf];W[fe]
C[... then jumped to 4, attacking the ones on the left. ]
;B[db]
LB[nf:3]
C[After Black defended with 3 and 5, ... ]
;W[if]
C[... White took the initiative at the top by capping with 6. Instead of being the attacker, Black was now the defender. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][fc][jd][ch][ce][dj][cn][ec][gd][hd][cf][oj][pb][qb][qc][rb]
AB[dp][pd][pp][dd][df][pf][jq][eg][fp][qj][ed][cd][fd][ge][bp][ph][pc][qd][rc]
LB[bp:1][oj:2][ph:3][qc:4][pc:5][pb:6][qd:7][rb:8][rc:9][qb:10]
C[Problem 107. Black to play.  

The game in Problem 103 continued with the sequence to White 10. Where should Black play next ? ]
(;B[me]
LB[mc:A]

TE[2]
C[Correct Answer.  

Black should jump to 1 to build influence facing the bottom and to stop White from expanding her territory at the top. Since Black is threatening to attach at A, ... ]
;W[ld]
C[... White will defend with 2. ]
;B[dc]
C[Next, Black should secure his stones in the upper left corner with 3. <= ]
)
(;B[ne]
C[How the game continued.  

Compared with the Correct Answer, Black 1 was lukewarm. It didn't have a good follow-up against White's position at the top. ]
;W[jo]
C[White switched to the bottom and capped with 2. ]
;B[mc]
C[If Black next attached at 3, ... ]
;W[md]
LB[rd:A]
C[... White could counterattack with 4 and fight fearlessly because, if her stones in the upper right corner get cut off, she can always live by capturing a stone at A. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][en][el][ej]
AB[dp][pd][pp][dd][jj][cj][dl][fp]
LB[el:7][ej:5][en:3][cn:1][cj:2][dl:6][fp:4]
C[Problem 108. Black to play.  

How should Black answer the attachment of White 7 ? ]
(;B[ei]
TE[2]
C[Correct Answer.  

It is senseless for Black to fight in the lower left because he is outnumbered there four stones to two. Instead, he should attach at 1. ]
;W[fi];B[eh];W[dj]
LB[fi:2]
C[White 2 and 4 are White's best moves, but ... ]
;B[ci]
LB[eh:3]
C[... Black builds a moyo in the upper left with 3 and 5. ]
;W[ck]
C[If White 6, ... ]
;B[fj]
C[... Black will cut at 7 and his moyo will become even bigger. <= ]
)
(;B[dk]
C[How the game continued.  

Black exchanged 1 ... ]
;W[ek]
C[... for White 2, but this left his stones heavy, so ... ]
;B[di]
C[... he had to defend the left side with 3. ]
;W[nq]
LB[dm:A]
C[Since she was not afraid of the double peep at A, she switched to the lower right with 4. ]
;B[dm]
C[If Black were to peep at 5, ... ]
;W[cp]
C[... White would make sabaki by attaching at 6. <= ]
)
)
(;
GM[1]
SZ[19]
AW[md][eb][fc][gd][eg][ch]
AB[dp][pd][pp][dd][pg][df][fd][fe][ck]
LB[ck:6][ch:5][eg:7][df:4][fd:8][fe:10][eb:11][fc:3][gd:9][md:1]
LB[pg:2]
C[Problem 109. Black to play.  

After White plays the diagonal move of 11, how should Black secure his stones in the corner ? ]
(;B[db]
TE[2]
C[Correct Answer.  

Black should attach at 1 and ... ]
;W[dc];B[cc];W[ec];B[cb]
LB[ic:A]
C[... the sequence to 5 will inevitably follow. White's stones at the top are heavy and Black is threatening to pincer at A, so ... ]
;W[ic]
C[... White must take this point herself with 6. ]
;B[cf]
LB[ej:B][di:A]
C[Next, Black secures the corner with 7, robbing White's stones on he left of a base. Next, Black A would be a strong attack against these stones, so White has to defend with a move around B. <= ]
)
(;B[cc]
LB[bf:A]
C[How the game continued.  

Black 1 also secured the corner, but the situation there is still undefined and White's stones at the top were light and flexible. In addition, the possibility of White A was an annoyance to Black. ]
;W[dn]
C[Since the two white stones in the upper left were in no immediate danger, White made an approach at 2, preparing to attack the black stone on the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][nq][er][fq][gp][co][cn][dm]
AB[dp][pd][pp][dd][jj][kc][nd][qn][cp][eq][dn][en]
LB[kc:6][nd:2][qf:1][qn:4][nq:3][cp:12][co:11][cn:5][dn:8][dm:9]
LB[en:10][eq:14][er:15][fq:7][gp:13]
C[Problem 110. Black to play.  

The sequence to White 15 in the lower left is a joseki. Where should Black play next ? ]
(;B[fp]
TE[2]
C[Correct Answer.  

Playing on top with 1 forces White ... ]
;W[fr]
C[... to connect at 2. ]
;B[dr]
C[Now Black can enclose the corner with 3. ]
;W[gn];B[fm]
LB[cm:A]
C[Black 5 aims to cut at A, so ... ]
;W[ck]
C[... White must defend at 6. ]
;B[bo]
LB[cr:B]
C[The sequence to Black 7 is a joseki. Black 7 is an important move because it prevents the clamp of White B. <= ]
)
(;B[dr]
C[How the game continued.  

Black 1 was careless. ]
;W[ep]
C[White ataried with 2, ... ]
;B[dq];W[kp]
LB[do:A]
C[... then took up a position at the bottom with 4. Next, White aimed at separating Black's stones by pushing through with A. If Black were to play A, White would strengthen her stones on the left side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nc][fc][jd][ch][ce][dj][cn][ec][gd][hd][cf][oj][pb][qb][qc][rb][dl][jo][qn][pn][pk][qk]
AB[dp][pd][pp][dd][df][pf][jq][eg][fp][qj][ed][cd][fd][ge][bp][ph][pc][qd][rc][cl][lp][np][qo][qi][ne]
LB[qi:7][pk:8][qk:6][pn:4][qn:2][qo:3][lp:1][np:5][cl:9][dl:10]
C[Problem 111. Black to play.  

The game in Problem 107 continued with the sequence to White 10. How should Black answer the move ? ]
(;B[ck]
TE[2]
C[Correct Answer.  

Black 1 ... ]
;W[dk];B[cm]
C[... 3 are the simplest way to play. ]
;W[dm]
C[White blocks at 4 and ... ]
;B[bn]
C[... Black links up to the bottom with 5. ]
;W[cb]
C[If White next robs the black group at the top of its base with 6, ... ]
;B[gg]
C[... Black will make shape by jumping to 7, reducing White's influence in the center. All of Black's stones are safe and he has secured about 30 points in the lower left. Together with his territory on the upper right side and the territory he has staked out in the bottom right, Black has a substantial lead. <= ]
)
(;B[cm]
C[Variation.  

Bumping against the white stone with Black 1 is also possible, but ... ]
;W[dm];B[bn];W[ck]
LB[bn:3]
C[... White can block with 4 after Black 3. Since White is now thick on the left side, ... ]
;B[dc]
C[... Black should secure his stones in the upper left with 5. ]
;W[bm]
C[Next, White squeezes Black ... ]
;B[bl];W[bo];B[am];W[cp];B[ao];W[co];B[cq];W[bq];B[ap];W[dq];B[cr];W[ep];B[do];W[dn];B[eo];W[eq]
C[... with the sequence to 22, but ... ]
;B[fq]
LB[fo:A]
C[... since the ladder at A is favourable for Black, he can play 23 and secure the territory in the lower left. Black has a won game. <= ]
)
(;B[dm]
C[How the game continued.  

Black haned with 1 and ... ]
;W[cm]
C[... White cut with 2. ]
;B[dk]
C[Next, Black tried to destroy White's territory on the left, but ... ]
;W[el];B[ek];W[ck];B[cj];W[bl];B[bk];W[cl];B[di];W[bj];B[ej];W[bi]
C[... White skilfully linked up with the sequence to 14 and the damage she suffered was small. On the other hand, the thickness White build up facing the bottom would adversely affect Black's moyo there. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][kc][nb][qf][ql][cn][bl][ck][dk][ej]
AB[dp][pd][pp][dd][db][df][hc][nd][qn][fp][bk][cj][bi]
LB[nb:1]
C[Problem 112. Black to play.  

White slides to 1, hoping to uproot the two black stones in the upper right corner. How should Black respond ? ]
(;B[qd]
TE[2]
C[Correct Answer.  

Black 1 forces White... ]
;W[pi]
C[... to reinforce the right with 2. ]
;B[oc]
C[Next, Black defends the corner with 3. Black is happy with this result because he has stabilised his stones in the corner and the white stones at the top are still unsettled. <= ]
)
(;B[pi]
C[Variation.  

Invading with Black 1 is also a strong move. ]
;W[qd]
C[White makes sabaki by attaching at 2. ]
;B[qc];W[pc];B[oc];W[pb];B[qe];W[rd];B[ob];W[pe];B[od];W[qb]
LB[re:B][rc:A]
C[After White 12, the points A and B are miai. ]
;B[rc]
C[If Black 13, ... ]
(;W[re]
C[... White can capture at 14. <= ]
)
(;B[pc]
C[How the game continued.  

Black 1 didn't put pressure on the right side, so ... ]
;W[rd]
C[... White could strengthen her stones there with 2 ... ]
;B[rc];W[qd];B[qc];W[ph]
C[... to 6. Compared with the Correct Answer, the territory Black got in the corner was smaller and White's stones at the top had more flexibility to withstand an attack. <= ]
)
(;W[rb]
C[White can also take two stones in the corner, ... ]
;B[re]
C[... letting Black play 15 ... ]
;W[sc];B[rf]
C[... and 17. <= ]
))
)
(;
GM[1]
SZ[19]
AW[md][eb][fc][gd][eg][ch][dn][ej]
AB[dp][pd][pp][dd][pg][df][fd][fe][ck][el][cc]
LB[ej:3][el:2][dn:1]
C[Problem 113. Black to play.  

After White 1 in the game continuation of Problem 109, Black 2 and White 3 were exchanged. What should Black do now ? ]
(;B[ek]
TE[2]
C[Correct Answer.  

Black 1 makes thick shape and prevents White's stones on the left separated. ]
;W[fn]
C[If White 2, ... ]
;B[fj]
C[... Black forces once with 3, ... ]
;W[ei];B[fp]
LB[gh:A]
C[... then jumps to 5. White is left with weak stones above and below. Black is aiming at A. If White A, Black attacks the two stones below. <= ]
)
(;B[cm]
LB[dl:A]
C[How the game continued.  

Black jumped to 1, defending his weak point at A, but ... ]
;W[cn]
C[... this move induced White to block with 2, weakening Black's stones below. ]
;B[fp];W[fn];B[gl];W[hn]
LB[cj:B]
C[Up to 6, White escaped into the center, leaving the black stones above and below weak. If Black defends the bottom, White can settle her stones by attaching at B. <= ]
)
)
(;
GM[1]
SZ[19]
AW[nq][cn][dm][co][fq][gp][fr][gn][ck]
AB[dp][pd][pp][dd][pn][dn][en][cp][fp][eq][kq][fm]
LB[pn:2][nq:1][kq:14][fp:10][eq:12][fr:13][fq:9][gp:11][gn:15][fm:16]
LB[en:6][dn:4][cp:8][co:7][cn:3][dm:5][ck:17]
C[Problem 114. Black to play.  

White just extended to 17. How should  Black attack the white stones in the bottom left ? ]
(;B[er]
LB[gm:B][ci:A]

TE[2]
C[Correct Answer.  

Black secures the corner with 1. He can now aim to attack the four white stones on the left with A. White will have to defend. Even so, Black B could become a good move which attacks both the white stones on the left and the ones at the bottom <= ]
)
(;B[hp]
C[Variation.  

Black 1 strikes at White's weak point. ]
;W[fo]
C[White ataries with 2 and ... ]
;B[ep];W[hq]
C[... tries to make shape with 4, but ... ]
;B[ho]
C[... Black forces with 5 ... ]
;W[go];B[iq]
C[... and 7. ]
;W[hr];B[oq]
C[He next exchanges 9 ... ]
;W[np]
C[... for 10, ... ]
;B[jo]
C[... then makes shape with 11. The white group on the left is still without eyes and the two stones on the right are heavy. Unfortunately, Black's stones in the bottom are left unsettled. <= ]
)
(;B[ko]
C[How the game continued.  

Black jumped to 1, strengthening his stones at the bottom and putting pressure on White's stones there. ]
;W[er]
C[But White counterattacked with 2 and ... ]
;B[dr];W[cr]
C[... took the corner with 4 ... ]
;B[es];W[cq];B[dq];W[bp]
C[... to 8. ]
;B[gq]
C[Black cut at 9, but ... ]
;W[fo]
C[... White forced with 10, ... ]
;B[ep];W[hq];B[gr];W[hr]
LB[hq:12]
C[... sacrifices three stones with 12 and 14, ... ]
;B[fs];W[in]
C[... then made shape with 16. The game was proceeding in White's pace. <= ]
)
)
(;
GM[1]
SZ[19]
AW[db][dc][cb][fb][fc][ed][fd][gd][jd][nc][re][pi][qi][pj][nq][jp][cn][dn]
AB[dp][pd][pp][dd][jj][bb][cc][cd][ec][eb][pf][pk][qk][qj][pn][co][fp][fn][cj][ee]
TR[re]
C[Problem 115. Black to play.  

The marked white stone makes a long slide under Black's two stones, hoping to uproot them. How should Black respond ? ]
(;B[rd]
TE[2]
C[Correct Answer.  

Black should defend the corner by attaching at 1. ]
;W[qe];B[qd];W[pe]
LB[qe:2]
C[White will play 2 and 4 to create weaknesses in Black's position, ... ]
;B[oe];W[qg]
C[... then link up her stones on the right side. ]
;B[nd];W[oc];B[od];W[lc];B[pc]
C[Black secures the corner with the sequence to 11. <= ]
)
(;B[qd]
C[How the game continued.  

Black 1 was a lukewarm move because ... ]
;W[qg]
C[... it enabled White to secure her stones on the right side with 2. ]
;B[ne]
C[Black then jumped to 3 and ... ]
;W[ld]
C[... White reinforced her position at the top with 4. Black's stones in the corner are not still secure, so White was able to make more gains by attacking them. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fq][jp][nq][md][nc][oc][re][rf][qf][pg][rc]
AB[dp][pd][pp][dd][cj][dn][pn][qj][pc][rd][qe][pf][nd][ne]
LB[rc:1]
C[Problem 116. Black to play.  

White attaches with 1, the weak point of Black's position. How respond Black respond ? ]
(;B[pb]
LB[sd:B][mc:A]

TE[2]
C[Correct Answer.  

Descending to Black 1 makes miai of the points A and B. ]
;W[sd]
C[If White links up with 2, ... ]
;B[mc]
(;W[lc];B[mb];W[lb];B[nb]
C[... Black will capture two white stones with the sequence to 7, settling his stones at the top. The three white stones at the top are still unsettled. <= ]
)
(;W[mb]
C[If White plays 4 here, ... ]
;B[lc]
C[... Black will extend to 5. White can live only by crawling along the second line, but this would give Black a huge advantage, so it is unplayable. <= ]
))
(;B[se]
C[How the game continued.  

Black haned with 1, but ... ]
;W[qc];B[qd];W[pb]
LB[qc:2]
C[... White linked up her stones at the top with 2 and 4. ]
;B[qg];W[of];B[pe];W[qh];B[rg];W[rh];B[sf]
C[Even though Black was able to capture three stones on the right with the sequence to 11, ... ]
;W[oh]
C[... White made shape with her stones on the right with 12. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fq][md][nc][oc][re][rf][qf][pg][rc][jc][lp]
AB[dp][pd][pp][dd][cj][dn][pn][qj][pc][rd][qe][pf][nd][ne]
LB[rc:1]
TR[jc]
C[Problem 117. Black to play.  

White has played the marked stone, so the position at the top is different from Problem 116. How should Black answer White 1 here ? ]
(;B[mc]
TE[2]
C[Correct Answer.  

Cutting at 1 creates defects in White's position. ]
;W[mb]
C[In order to save her two stones at the top, White plays 2 ... ]
;B[lc];W[lb]
C[... and 4. ]
;B[se]
C[Black then switches back to the corner with 5. ]
;W[qc];B[qd];W[pb]
C[If White now tries to link up with the sequence to 8 - as in the game in Problem 116 - ... ]
;B[ob]
LB[nb:B][qb:A]
C[... Black cuts at 9. Whether White plays A or B, the two white stones in the corner will die. <= ]
)
(;B[pb]
C[How the game continued.  

Black descended with 1 as in the Correct Answer in Problem 116, but ... ]
;W[sd]
C[... White could still link up with 2. ]
;B[mc]
C[When Black cut with 3, ... ]
;W[mb];B[lc];W[lb];B[kc];W[kb]
TR[jc]
C[... White drove the cutting Black stone towards her marked stone, so White was able to live at the top ... ]
;B[le]
C[... in sente as well as wiping out Black's territory in the corner. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][nq][er][fq][gp][co][cn][dm][cc][dc][fc][gd][cf]
AB[dp][pd][pp][dd][jj][kc][nd][qn][cp][eq][dn][en][dq][dr][qj][qe][cd][fd][fe]
LB[cf:2][cc:8][dc:10][cd:9][fc:4][gd:6][fd:5][fe:7][qe:3][qj:1]
C[Problem 118. Black to play.  

This position arose from the game in Problem 110. How should Black answer White 10 ? ]
(;B[ec]
TE[2]
C[Correct Answer.  

Black must wedge in with 1 to create defects in White's position. ]
;W[eb];B[ed];W[gb];B[ge];W[hd]
C[The moves to White 6 are a joseki. ]
(;B[di]
C[Black should now attack the lone white stone on the upper left side with a high pincer at 7, which also aims at the three white stones below. ]
;W[eg];B[fi];W[gg];B[he];W[ie];B[hg];W[gh];B[if]
LB[hj:A][je:B]
C[After 15, White's stones on the upper left are in trouble. If White A, Black will rescue his two stones on the left by attacking the three white stones below. He will then make a huge moyo in the top right with an atari at B. If White B, Black engulfs the four white stones above with A. <= ]
)
(;B[ci]
C[Variation.  

The low pincer of Black 7 is also possible. ]
;W[dh];B[di];W[eh];B[ch];W[cg];B[ef]
C[Black 13 gives White bad shape, but ... ]
;W[eg]
C[... Black could easily get into trouble in the fighting that would follow, whereas the result in the Correct Answer is clearly good for Black. <= ]
))
(;B[hc]
C[How the game continued.  

Black 1 was bad style. It didn't help Black; ... ]
;W[gc]
C[... it only strengthened White's position, eliminating a serious defect. ]
;B[be];W[bc]
(;B[bf];W[ch]
C[After White 6, Black was in trouble. <= ]
)
(;B[ch]
C[If Black had pincered with 5, ... ]
;W[bf]
C[... White would then have descended to 6, threatening to link up. ]
;B[dk]
C[Black might then have pincered at 7 and a difficult fight would have followed. <= ]
))
)
(;
GM[1]
SZ[19]
AW[mc][pc][qc][rj][pn][qn][qf]
AB[dp][pd][pp][dd][qd][oe][me][pj][qo][np]
LB[qf:3][mc:7][pc:11][qc:9][qd:10][oe:8][me:12][rj:13][pn:5][qn:1]
LB[np:2][qo:4]
C[Problem 119. Black to play.  

White 13 slides under the black stone at 6, intending to destroy Black's moyo on the right. How should Black respond ? ]
(;B[qj]
TR[rj]

TE[2]
C[Correct Answer.  

White 13 in the Problem Diagram (the marked stone) is the kind of move that panics a kyu player. We saw one way to play in such a position in the game continuation of Problem 93. Here is a simpler way. Black bumps with 1. His strategy is to stay on top and ... ]
;W[ri];B[rk];W[rl];B[qk];W[sk];B[qh];W[rh];B[qg];W[rg];B[pf]
C[... force White into a low position along the second line with the sequence to 11. ]
;W[re]
LB[rd:A]
C[After White 12, Black doesn't mind if White links up to the top with a move on the second line at A. ]
;B[nn]
C[Instead, he will take the strategic point of 13 and White will have a hard time breaking into Black's center. In a handicap game, it is always good for Black to force White to make life on the second line in exchange for influence. <= ]
)
(;B[nn]
C[How the game continued.  

Black capped with 1 and ... ]
;W[qh]
C[... White defended the right side with 2. ]
;B[oh]
LB[oi:A]
C[Black made influence in the center with 3, but his stones were thin because the threat of White A remained. ]
;W[iq]
C[White ended in sente, so she next took up position at the bottom with 4 ... ]
;B[gq];W[lq]
C[... and 6. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ci][cn][md][mg][db][fc][hd][cb]
AB[dp][pd][pp][dd][cc][df][fp][jd][jf][jh][pf]
LB[cb:1]
C[Problem 120. Black to play.  

White pushes into the corner with 1, robbing the black stones of their base. What should Black do ? ]
(;B[gf]
TE[2]
C[Correct Answer.  

Black jumps to 1, ... ]
(;W[bb]
C[... letting White take away his base with 2, but ensuring that his stones on the left are linked up to the center. ]
;B[mi]
C[Next, Black attacks by capping with 3. <= ]
)
(;W[mi]
LB[bb:@]
C[Instead of White @, jumping to 2 is better, but ... ]
;B[ck]
C[... Black would then invade at 3. The lesson here is that neither side should play moves on the second line in the opening. <= ]
))
(;B[bb]
LB[gg:A]
C[How the game continued.  

Black defended at 1. Although the stones at the top didn't have eyes, they could still jump to A, attacking the three stones at the top. ]
;W[en]
C[Before doing so, White strengthened the left side with 2 ... ]
;B[gn];W[mi]
C[... and the top with 4. ]
;B[gf]
C[Even if Black attacks the four white stones with 5, they should have no problem living. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][dk][dn][cn][bm][ho][hq][nq][ol][ql][qc][qd][rf][rg][nc]
AB[dp][pd][pp][dd][gc][bn][bo][co][fp][fq][fn][pn][nn][qj][pc][pe][qf][qg]
TR[rg]
C[Problem 121. Black to play.  

White tries to expand her corner by crawling with the marked stone. How should Black counter this move ? ]
(;B[qb]
TE[2]
C[Correct Answer.  

White's stones in the corner are thin, so Black can get massive thickness and confine White to the corner by playing the hane of 1. ]
;W[qe];B[rc];W[rd];B[sd];W[re];B[qh];W[rb];B[pb];W[ra]
LB[sb:A]
C[The sequence to White 10 is inevitable. White cannot omit 10 because Black is threatening to start a ko with A. ]
;B[lc]
C[Finally, Black pincers with 11 and his moyo at the top is nearly impregnable. ]
;W[ml]
C[Next, White must run away with B, since a black move there would completely crush her. <= ]
)
(;B[qh]
C[How the game continued.  

Black extended with 1, but ... ]
;W[pb];B[ob];W[qb]
LB[pb:2]
C[... this enabled White to secure the corner with the hane and connection of 2 and 4. ]
;B[oc]
C[White ended in sente, so ... ]
;W[rn]
C[... she took her opportunity to stabilise her stones on the lower right ... ]
;B[qo];W[ro];B[rp];W[qk]
C[... with the sequence to 10. <= ]
)
)
(;
GM[1]
SZ[19]
AW[gd][nc][qc][qd][pf][cn]
AB[dp][pd][pp][dd][df][kd][pc][oe][fp]
LB[qd:11][pc:10][qc:9][oe:8][pf:7][kd:6][nc:5][fp:4][cn:3][df:2]
LB[gd:1]
C[Problem 122. Black to play.  

What should Black do after White plays 11 ? ]
(;B[qb]
TE[2]
C[Correct Answer.  

Black 1 forces White ... ]
;W[rb];B[pb];W[pe]
LB[rb:2]
C[... to secure the corner with 2 and 4. ]
;B[nd]
TR[nc]
C[Next, Black subdues the marked white stone with 5. It will now be almost impossible for White to escape with this stone. Even if it could escape, it would only make Black thick in the center. <= ]
)
(;B[pe]
C[How the game continued.  

Black forced with 1 ... ]
;W[qe];B[of]
C[... and 3, ... ]
;W[pg]
(;B[qm]
C[... then strengthened his stone in the lower right with 5. ]
;W[ld]
C[But Black's moyo at the top was still thin and ... ]
;B[le];W[kc];B[jc];W[jd];B[ke];W[ic];B[jb];W[ib];B[je];W[id];B[cj];W[lc]
C[... White managed to live at the top with the sequence to 18. ]
;B[me]
C[This was a big loss for Black.  <= ]
)
(;B[og]
LB[qm:@]
C[Variation.  

Instead of @ in the game, Black should have exchanged 5 ... ]
;W[ph]
C[... for White 6, ... ]
;B[jc]
C[... then played the diagonal move of 7. This last move would have secured the top right and restricted the white stone in the top left. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cm][dm][em][fm]
AB[dp][pd][pp][dd][cn][dn][en][jj]
LB[cn:2][dn:4][en:6][cm:3][dm:1][em:5][fm:7]
C[Problem 123. Black to play.  

White has extended to 7. Can Black ignore this move and play somewhere else, or does he have to defend ? ]
(;B[cg]
TE[2]
C[Correct Answer.  

Black's stones in the lower left are strong, so he should extend to 1, neutralising White's wall and limiting White's expansion to A. ]
;W[fn]
C[If White turns at 2, ... ]
;B[fp]
C[... Black defends the bottom with 3. <= ]
)
(;B[fp]
C[How the game continued.  

Black reinforces the bottom with 1, but ... ]
;W[cf]
LB[cq:A]
C[... White 2 was an ideal extension. Black had invested a lot of stones at the bottom, but the territory there was not secure, since White could invade at A. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ci][cn][md][mg][db][fc][hd][cb][en][mi][dk]
AB[dp][pd][pp][dd][cc][df][fp][jd][jf][jh][pf][bb][gn][dl]
LB[dl:1][dk:2]
C[Problem 124. Black to play.  

The game in Problem 120 continued with the exchange of Black 1 for White 2. What should Black do next ? ]
(;B[ck]
TE[2]
C[Correct Answer.  

Black 1 is a strong move. ]
;W[ek]
C[If White extends to 2, ... ]
;B[cj];W[di];B[el];W[fl];B[cm]
C[... Black makes shape with the sequence to 7. ]
(;W[bn]
C[If White 8, ... ]
;B[fm]
C[... Black hanes at 9, splitting the white stones above from the ones below. <= ]
)
(;W[fm]
C[If White 8 here, ... ]
;B[co]
C[... Black links up with 9. <= ]
)
(;W[cp]
TR[cm]
C[Continuation.  

After Black played the marked stone, White might make sabaki with 8, but ... ]
;B[fm];W[em];B[bn];W[bo];B[dj];W[ej];B[bm];W[do];B[fk];W[gl];B[ei];W[fj];B[gk];W[hl];B[bi];W[fi];B[eh]
C[... Black secures a large territory on the left with the sequence to 18, ... ]
;W[hj];B[dq];W[cq];B[ip]
LB[dq:27]
C[... then secures some more stones at the bottom with 27 and 29. <= ]
))
(;B[el]
C[How the game continued.  

Black 1 revealed a negative attitude. ]
;W[cl];B[ck];W[bk];B[cm];W[bl];B[dm];W[bm]
C[White was able to link up her stones on the left and take some profit with the sequence to 8. ]
;B[dn]
C[If Black were to play at 9 after this, ... ]
;W[co]
LB[do:A]
C[... White would extend to 10 ant threaten to push in at A. ]
;B[do]
C[Therefore, Black would defend there and White would wrest the corner away from Black. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cf][dk][dn][cn][bm][ho][hq][nq][ol][ql][qc][qd][rf][rg][cd][dc][hc][pb][qb][nc][fs][gs][gr][jq][kq][qk][ro][rn][sp][rq][qq][lr][lp]
AB[dp][pd][pp][dd][gc][bn][bo][co][fp][fq][fn][pn][nn][qj][pc][pe][qf][qg][cc][gd][ob][oc][fr][dr][es][qh][qo][qp][rp][oq][nr][mr][mq][lq][kp][ko]
LB[cd:1][dc:3][cc:2]
C[Problem 125. Black to play.  

This position arose later in the game in Problem 121. White attaches with 1, then crosscut with 3. How should Black continue ? ]
(;B[cb]
TE[2]
C[Correct Answer.  

The proverb advises extending when caught in a crosscut. Descending to Black 1 is the best move. ]
;W[bd];B[ec];W[de];B[ed]
C[Black and White settle the upper left with the sequence to 5. ]
;W[kc]
C[White uses her sente to stake out a position at the top, but ... ]
;B[nd]
C[... Black will block at 7. With Black's thick positions on the left and right, White is going to run for her life. <= ]
)
(;B[ed]
C[How the game continued.  

Extending to Black 1 here was also a good move, but ... ]
;W[bc];B[cb];W[be];B[bb];W[ab];B[ec];W[kc]
C[... White's shape in the upper left ended up with a bit more eye potential than in the Correct Answer. In any case, the result here was almost the same. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][co][cn][dm][cj][nq][qq][qp][pn]
AB[dp][pd][pp][dd][cf][db][en][dn][cp][jq][oo][pq]
LB[fc:1][cf:2][db:11][cp:8][co:7][cn:3][dn:4][dm:5][en:6][cj:9]
LB[jq:12][nq:11][oo:14][pn:13][qq:15][qp:17][pq:16]
C[Problem 126. Black to play.  

How should Black respond to White 17 ? ]
(;B[on]
TE[2]
C[Correct Answer.  

Pushing out with Black 1 ... ]
;W[pm];B[om]
C[... and 3, aiming to make a moyo at the bottom, is a good strategy. ]
;W[po];B[op];W[pl]
C[White will secure the right side with the sequence to 6, but ... ]
;B[jo]
C[... Black can then reinforce the bottom by jumping to 7. It will be now very hard for White to invade this huge valley of territory. <= ]
)
(;B[qr]
C[How the game continued.  

The hane of Black 1 was also a good move in this position. ]
;W[po]
C[White settled her stones on the right with 2, ... ]
;B[np];W[mp];B[mo];W[lp]
LB[mp:4]
C[... then pulled out her stone at the bottom with 4 and 6. This was, however, an overplay. White's stones are heavy and vulnerable, while Black's are strong and flexible. See Problem 130 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cm][dm][em][fm][cf][fc]
AB[dp][pd][pp][dd][cn][dn][en][jj][fp][ef]
LB[fc:2][ef:1]
C[Problem 127. Black to play.  

The game in Problem 123 continued with the moves of Black 1 and White 2. Where should Black play next ? ]
(;B[dc]
TE[2]
C[Correct Answer.  

Black makes an iron pillar with 1, ... ]
;W[ic]
C[... inducing White to defend the top by extending to 2. ]
;B[cg]
C[Next, Black 3 is a severe attack. ]
;W[bg];B[ch];W[df]
C[White resists with 6, but ... ]
;B[eg]
LB[dc:1][cc:A]
C[... Black simply extends to 7, making thickness in the center. White's three stones on the upper left side might be able to live, But Black's resulting thickness will neutralise White's four-stone wall below. You might wonder why Black doesn't anchor his stones to the 3-3 point at A as in Problem 74 instead of playing 1. The reason is ... ]
;W[ee]
C[White might try to separate the black stones by exchanging 8 ... ]
;B[de]
C[... for 9 later in the game, but ... ]
;W[bh]
C[... White will have to take care of her stones on the left, so she can't do this in sente. ]
;B[fe];W[ed];B[gc];W[gb];B[fb]
TR[ee][ed]
C[Therefore, Black will be able to link up with the crosscut tesuji of 15. The white marked stones can't avoid being captured. <= ]
)
(;B[fd]
C[How the game continued.  

Black secured a link to his stones on the outside with 1, but ... ]
;W[gd]
C[... this attachment needlessly strengthened White's stones. ]
;B[fe];W[cc];B[ec];W[gc];B[cd];W[bd];B[bb];W[bc];B[cb];W[dh]
C[With the sequence to 12, White secured territory on the left side and her three stones at the top were now resilient enough to survive any attack. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][pl][pn][lo][lq][nr][lm]
AB[dp][pd][pp][dd][jj][nd][np][pq][nn][nl][ip]
LB[qf:1][nd:2][ip:6][lm:11][lo:9][lq:5][nr:7][pq:8][np:4][nn:10]
LB[nl:12][pl:13]
C[Problem 128. Black to play.  

A sharp skirmish has taken place in the lower right with the sequence to 13. How should Black continue ? ]
(;B[pj]
TE[2]
C[Correct Answer.  

Even though there are many open areas where Black can stake out territory, it is more urgent for him to press his advantage on the right with Black 1. ]
;W[ok]
C[White must escape with 2, but ... ]
;B[pg]
C[... Black attacks the white stone above with 3 ... ]
;W[pf];B[og]
C[... and builds influence with 5. ]
;W[of]
C[If White next plays 6, ... ]
;B[ng];W[nk];B[ml]
C[... Black will be satisfied with the result after the sequence to Black 9. While White is trying to escape with her stones on the right side, she will be unable to make any territory, but Black will be building up influence and the white stones at the bottom will come under attack. <= ]
)
(;B[qi]
C[How the game continued.  

Black 1 was too low an invasion in this position. ]
;W[pj];B[pi];W[oj]
LB[pj:2]
C[White moved out into the center with 2 and 4. ]
;B[mk]
C[Black could not allow his stones in the lower right to be confined to the corner, so he played 5, ... ]
;W[qj]
C[... enabling White to settle her stones on the right with 6 and rob the two black stones of a liberty. Now Black was the one under attack. See Problem 132 for the continuation. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cn][cq][dq][er][fq][gr][gp][hp]
AB[dp][pd][pp][dd][jj][dj][cp][ep][eq][fp][fo][go]
LB[dj:2][cn:1][cp:8][ep:12][eq:10][fp:4][fo:6][go:14][gp:5][hp:15]
LB[fq:3][cq:7][dq:9][er:11][gr:13]
C[Problem 129. Black to play.  

What should Black do after White 15 ? ]
(;B[ho]
LB[ip:A]

TE[2]
C[Correct Answer.  

Black should push with 1, threatening to hane at A. ]
;W[io]
C[White cannot let this happen, so she will hane at 2. ]
;B[in]
C[Next, Black exchanges 3 ... ]
;W[jo]
C[... for White 4, ... ]
;B[cj]
C[... then secures the left side with an iron pillar at 5. Black has taken a big lead in the opening of this five-stone handicap game. <= ]
)
(;B[dm]
C[How the game continued.  

Attacking the lone stone on the left side with 1 was a backward move which resulted in Black's stones in the lower left becoming overconcentrated. ]
;W[cf]
LB[bj:A]
C[White responded with an approach move at 2 which left open the possibility of reducing Black's territory in the lower left by sliding to A. ]
;B[fd]
C[(This move is here meant to get 'White to move'.) ]
;W[bp]
C[White could also reduce this territory by playing the sequence from 4 ... ]
;B[bo];W[bq];B[co]
C[... to Black 7. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][co][cn][dm][cj][nq][qq][qp][pn][po][lp][mp]
AB[dp][pd][pp][dd][cf][db][en][dn][cp][jq][oo][pq][qr][np][mo]
TR[lp]
C[Problem 130. Black to play.  

How should Black answer White's extension with the marked stone (White 6 in the game continuation of Problem 126) ? ]
(;B[jo]
TE[2]
C[Correct Answer.  

By jumping to 1, Black attacks the three white stones and expands his moyo on the left. ]
;W[lo]
C[White must escape into the center with 2 ... ]
;B[mn];W[ln]
C[... and 4. ]
;B[mm]
LB[mn:3]
C[After Black 3 and 5, ... ]
;W[lm]
C[... White will probably exchange 6 ... ]
;B[ml]
LB[pr:A]
C[... for Black 7. Black has nothing to worry about, but he must be careful about the bad aji of White A. <= ]
)
(;B[lr]
C[How the game continued.  

Black 1 also attacked the white stones, but it is small. ]
;W[on];B[or];W[nn];B[no];W[jp];B[ip];W[ln];B[mq]
C[Up to 9, Black lived, but he was confined to the bottom and ... ]
;W[iq];B[kp];W[jo];B[hq];W[ir];B[jr];W[hr];B[gq];W[ko]
C[... White built a wall facing the center with the sequence to 18. ]
;B[kq];W[qf]
C[White next approached with 20 and built a vast moyo on the right side. <= ]
)
)
(;
GM[1]
SZ[19]
AW[hc][bd][cf][ci][cn][qn][qh][og][mh][pc][oc][ob][nc][md][me][ke]
AB[dp][pd][pp][dd][cc][fc][fp][jq][np][pk][nf][mf][lf][ne][nd][pf][qc][qb][pb]
TR[ke]
C[Problem 131. Black to play.  

White has just jumped with the marked stone, threatening to engulf a large area at the top. Taking a global view of the position, where is the best point for Black to play ? ]
(;B[qj]
LB[qp:B][oh:A]

TE[2]
C[Correct Answer.  

Black 1 is a powerful move. It aims at either A, which takes the territory in the upper right, or B, which encloses the corner and attacks the lone white stone in the lower right. ]
;W[rp]
C[Aji  

(This white move is here necessary to get "Black to move'.) ]
;B[dj]
C[Later, if Black can exchange 3 ... ]
;W[cj]
C[... for White 4, ... ]
;B[id]
C[... he can exploit White's bad aji at the top by playing the shoulder hit of 5. ]
;W[ic];B[jd];W[jc];B[kd];W[kc];B[mc];W[lc];B[mb];W[lb]
C[If White resists with the sequence to 10, ... ]
;B[ld]
C[... White's position at the top collapses when Black ataris with 11. ]
;W[le];B[kf];W[je];B[ie]
TR[dj]
C[Because of the marked black stone, the white stones will be captured in a ladder. <= ]
)
(;B[bc]
C[How the game continued.  

Black 1 had only one aim: to secure the stones in the upper left corner. While it is a good move locally, it failed to take a global view of the board and had almost no attacking potential. Such moves are always bad. ]
;W[rk]
C[White took this pause in the fighting to give her stones on the right some flexibility by sliding to 2, neutralising the effect of Black's wall above. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qf][pl][pn][lo][lq][nr][lm][oj][qj][pj][ni]
AB[dp][pd][pp][dd][jj][nd][np][pq][nn][nl][ip][mk][qi][pi][oi]
LB[oi:1][ni:2][pg:A]
C[Problem 132. Black to play.  

In the game continuation of Problem 128, Black should have jumped to A. Instead he exchanged 1 for White 2, which weakened his stones below. How can Black savage the position ? ]
(;B[nj]
TE[2]
C[Correct Answer.  

Black should cut with 1. Even though the three black stones on the right are short of liberties, they still have enough room to escape. ]
;W[mi]
C[When White extends to 2, ... ]
;B[pg]
C[... Black escapes by jumping to 3. ]
;W[lk]
C[White can confine Black to the lower right by attaching with 4, but ... ]
;B[lj]
C[... Black counterattacks with the hane of 5. ]
;W[mj];B[nk];W[ll]
LB[nm:A]
C[When White connects at 8, she is threatening the wedge in at A (Do you see the danger ?). Black must take defensive action. Next ... ]
;B[mn]
C[... Black must first peep with 9 ... ]
;W[ln];B[mp]
C[... and 11, ... ]
;W[lp];B[qn];W[qo];B[po]
LB[qn:13]
C[... then attach and cut with 13 and 15, leaving the eight white stones an the bottom without eyes. ]
;W[qm];B[rn];W[ro];B[on];W[pm];B[rp];W[rm];B[li]
C[Black has a won game. <= ]
)
(;B[og]
C[How the game continued.  

Jumping to 1 revealed a negative attitude. ]
;W[mj]
LB[oo:B][pg:A]
C[White connected with 2 and her stones on the right became strong because they had access to the center. In the upper right, White can aim at breaking Black's shape by playing on the vital point of A, perhaps living there as well. In the lower right, the peep at White B will also be troublesome for Black. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cc][cd][ce][df][dg][eg][fc][kc]
AB[dp][pd][pp][dd][jj][de][ee][ef][dc][fg][gf][id]
LB[kc:1]
C[Problem 133. Black to play.  

White has played 1, threatening to rob Black of his hard-earned profit. How should Black respond ? ]
(;B[mc]
TE[2]
C[Correct Answer.  

The pincer of Black 1 shows a positive attitude. ]
;W[ke]
C[If White jumps to 2, ... ]
;B[me]
C[... Black follows her out with 3 and, ... ]
(;W[ib]
C[... if White slides to 4, ... ]
;B[lg]
C[... Black keeps White hemmed in with 5. Even if White manages to live at the top, Black's moyo on the right more than compensates for the loss. <= ]
)
(;W[kg]
C[If White 4 here, ... ]
;B[pj]
C[... Black can take the big point at 5 on the right and White's stones are still unsettled. <= ]
))
(;B[ic]
C[How the game continued.  

Black played 1 and ... ]
;W[nc]
LB[ec:E][cb:D][eb:C][db:B][jb:A]
C[... White was happy to settle her stones at the top by extending to 2. Later, White had two sente endgame moves: one at A, and the other at B, followed by Black C - White D - Black E. Thus, Black's territory was not at all that big. Black was thick, but using thickness to make territory is always bad. Thickness should be uses for attacking as in the Correct Answer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[hc][bd][cf][ci][cn][qn][qh][og][mh][pc][oc][ob][nc][md][me][ke][hq][rk]
AB[dp][pd][pp][dd][cc][fc][fp][jq][np][pk][nf][mf][lf][ne][nd][pf][qc][qb][pb][bp][bc]
LB[bp:1][hq:2]
C[Problem 134. Black to play.  

The game in Problem 131 continued with Black jumping down to 1 and White invading with 2. How should Black respond ? ]
(;B[fq]
LB[ho:A]

TE[2]
C[Correct Answer.  

Black 1 defends the corner and severely attacks the invading white stone. If White runs away into the center, her stones will be heavy and Black will gain more profit by attacking them. ]
;W[kq]
C[Therefore, she attaches at 2 and tries to make a base at the bottom right ... ]
;B[jp];W[jr];B[ir];W[lr];B[js];W[kr];B[iq];W[oq];B[pq];W[op];B[oo];W[nq]
C[... with the sequence to 14. ]
;B[qo]
C[However, Black secures the territory at the bottom left as well as in the lower right corner, while White's stones there are still not secure. <= ]
)
(;B[jo]
C[How the game continued.  

Black 1 was a slack move. ]
;W[eq]
C[White stabilised her stones at the bottom ... ]
;B[ep];W[fq];B[dq];W[gp];B[cl];W[gn]
C[... with the sequence to 8. ]
;B[dm]
LB[qq:A][jr:B]
C[Next, White can invade at A. Depending on how Black responds, White B could become a big endgame move. The balance of territory was now beginning to look unfavourable for Black. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][fd][ge][he][hd][md][cn][ch]
AB[dp][pd][pp][dd][df][fe][ff][gf][gd][pf][fp]
LB[df:4][ch:7][cn:5][fp:6][fc:3][fd:9][gd:8][hd:13][he:15][ge:11]
LB[fe:10][ff:12][gf:14][md:1][pf:2]
C[Problem 135. Black to play.  

How should Black continue after White connects with 15 ? ]
(;B[ck]
TE[2]
C[Correct Answer.  

Now is the time to invade the left side because Black is thick above and also strong below. ]
;W[ei]
C[White jumps into the center with the knight's move of 2, keeping away from Black's thickness. ]
;B[ek];W[gi]
C[After White 4, ... ]
;B[co]
C[... Black exchanges 5 ... ]
;W[dn]
C[... for 6 to make White heavy, ... ]
;B[gk]
C[... then jumps to 7. White's two groups on the left side are in trouble; even if she saves one of them, the other could die. <= ]
)
(;B[hf]
C[How the game continued.  

Black increased his thickness with 1, but this move had no severe follow-up at the top, so ... ]
;W[dk]
C[... White was able to secure her stones on the left with 2. Black lost his chance to take a decisive lead. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fd][ec][dc][cc][df][cl][el][fq][lq]
AB[dp][pd][pp][dd][cd][ed][fe][ci][ei][dn][fn][nq]
TR[df]
C[Problem 136. Black to play.  

The marked white stone is on the vital point. How does Black make good shape ? ]
(;B[bc]
TE[2]
C[Correct Answer.  

Black's stones are short of liberties, but, by playing 1, he makes White's stones short of liberties too. ]
;W[bb]
C[White blocks at 2 and, ... ]
;B[bd]
C[... when Black connects at 3, ... ]
;W[gd]
LB[fc:A]
C[... White must extend to 4 to defend against the cut at A. ]
;B[ef]
C[With 5, Black secures the territory in the upper left. <= ]
)
(;B[gd]
C[How the game continued.  

Black 1 was sente, but it was bad because it strengthened White and eliminated her bad aji. ]
;W[fc];B[bc];W[bb];B[bd];W[ge];B[ff];W[he];B[gi]
C[After the sequence to Black 9, ... ]
;W[ee]
C[... White cut at 10 and it was Black who was left with bad aji. <= ]
)
)
(;
GM[1]
SZ[19]
AW[fc][kc][nb][qd][rd][qf][ph][ql][dr][fr][hq][go][cn][bl][cl][ak][ck][dk][ej]
AB[dp][pd][pp][dd][db][df][gd][hc][nd][pc][qc][rc][qn][kq][fp][co][dn][bm][cm][bk][cj][bi]
TR[ak]
C[Problem 137. Black to play.  

White has just ataried with the marked white stone. How should Black respond ? ]
(;B[oq]
TE[2]
C[Correct Answer.  

Defending the lower right with 1 is a big move; the corner alone is worth 15 points. ]
;W[bj]
C[If White captures a stone with 2, ... ]
;B[qj]
C[... Black will invade at 3, destroying White's only substantial territory. Black has an unassailable lead. <= ]
)
(;B[bj]
C[If Black connects.  

If Black connects at 1, ... ]
;W[pq]
C[... White can attach at 2 and live in the corner ... ]
;B[oq];W[qp];B[po];W[pr];B[or];W[ro];B[rn];W[rr]
C[... with the sequence to 10. White's territory there is worth 9 points, so Black 1 in the Correct Answer is worth more than 25 points. ]
;B[qj]
C[In any event, Black is still in the lead and the invasion at 11 is his biggest move. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][hc]
AB[dp][pd][pp][ec]
LB[cd:1][ec:2][hc:3]
C[Problem 138. Black to play.  

This is a fundamental three-stone handicap position. How should Black continue ? ]
;B[ef]
TE[2]
C[Correct Answer.  

Jumping to 1, ... ]
;W[cg]
(;B[dh];W[ch];B[di];W[ci];B[dj];W[ck];B[de]
C[... then plastering White against the left side with the sequence to 9, is a good strategy in a three-stone handicap game. ]
;W[ce];B[kd]
C[Black can now use this thick wall to attack the white stone at the top with the pincer of 11 ... ]
;W[he];B[hg]
C[... and the cap of 13. The two white stones at the top are now on the run. By chasing these stones, Black will be able to make territory at the top and thickness in the center. <= ]
)
(;B[kd]
LB[cg:2]
C[Variation.  

Making a pincer immediately after White extends to 2 is also good, but it lacks the severity of the sequence in the Correct Answer. ]
;W[ge]
C[White plays the vital point of 4 and ... ]
;B[cc];W[bc];B[dd];W[ce];B[eh];W[cb]
C[... secures the corner with the sequence to 10. ]
;B[pj]
C[Black 11 is big, but Black's stones in the upper left are still not settled. Black can play this way if he is confident of his fighting ability. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][bc][be][gc]
AB[dp][pd][pp][cc][dc][ed]
LB[cd:1][ed:2][gc:3][cc:4][bc:5][dc:6][be:7]
C[Problem 139. Black to play.  

The moves to White 7 are a joseki. What should Black do next ? ]
;B[fe]
TE[2]
C[Correct Answer.  

Black 1 is the vital point. ]
(;W[dg]
C[If White defends the left side with 2, ... ]
;B[hd]
C[... Black plays 3 ... ]
;W[ic];B[hc];W[hb];B[gd]
C[... to 7 to get a thick position. ]
(;W[fc]
C[If White 8, ... ]
;B[gb]
C[... Black will cut at 9. <= ]
)
(;W[gb]
C[If White 8 here, ... ]
;B[je]
LB[jc:A]
C[... Black will play the knight's move of 9, increasing his thickness in the center and threatening to attach at A next. <= ]
))
(;W[id]
C[Variation.  

If White defends the top with 2, ... ]
;B[cf]
C[... Black attacks the white stones on the left with 3. ]
;W[cg]
C[White settles her stones with the tesuji of 4, but, ... ]
;B[dg];W[bg];B[dh]
C[... up to 7, Black gets thickness, ... ]
;W[ci];B[kd]
C[... enabling him to attack White at the top with the pincer of 9. <= ]
)
)
(;
GM[1]
SZ[19]
AW[bc][cd][ce][ic][oq][qr][np][bp][cn][dl][ci]
AB[dp][pd][dd][cc][cb][ec][qj][qp][pn][kp][fp][cq]
C[Problem 140. Black to play.  

In this two-stone handicap game, it is Black's turn to play. How should he attack the lone white stone at the top ? ]
(;B[de]
TE[2]
C[Correct Answer.  

Black must first press White against the left side with 1 ... ]
;W[df];B[ef]
C[... and 3. ]
;W[dg];B[kc]
C[Now he can pincer with 5. ]
;W[ie]
C[If White jumps to 6, ... ]
;B[ke]
C[... Black keeps up the pressure with 7. A large-scale black moyo is beginning to take shape on the right side. <= ]
)
(;B[kc]
C[Failure.  

If Black pincers at 1 without making any preparatory moves on the left, ... ]
;W[ef]
C[... White will reach out to her stone with the knight's move 2. <= ]
)
(;B[ef]
C[Failure.  

The knight's move of Black 1 is not forceful enough. ]
;W[lc]
C[White can take up a position at the top with 2 and Black has lost the initiative here. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ic][bc][cd][ce][ch][cn][qn]
AB[dp][pd][pp][dd][cc][cb][ec][kc][fp]
LB[kc:1][qn:2]
C[Problem 141. Black to play.  

White doesn't answer Black's pincer at 1. Instead she makes an approach move in the lower right with 2. What should Black do ? ]
(;B[de]
TE[2]
C[Correct Answer.  

Just as in Problem 140, Black should press White with 1 ... ]
;W[df];B[ef]
C[... and 3. ]
;W[dg]
C[This time, however, Black is one move ahead at the top, so ... ]
;B[je]
C[... the white stone there will come under great pressure when Black plays the knight's move of 5. <= ]
)
(;B[nq]
C[Failure.  

Answering White's approach move with 1 loses the initiative at the top. ]
;W[ef]
TR[ic]
C[White jumps to 2, taking the pressure off her marked stone. In an handicap game, Black must be more aggressive. When White plays her first move in the upper left corner, she is outnumbered, so Black should strive to keep his advantage at the top with a well-times pincer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][dc][ec][cf][ri][qf][of][rd]
AB[dp][pd][pp][pi][qc][nd][jd][fc][fd][ed]
LB[nd:4][qc:6][rd:5][qf:1][of:3][ri:7][pi:2]
C[Problem 142. Black to play.  

The joseki to White 7 has been played in the upper right corner. Where should Black play next ? ]
(;B[jp]
TR[pi]

TE[2]
C[Correct Answer.  

Black should treat his marked stone lightly and make a sanren-sei at the bottom. ]
;W[qn]
C[If White approaches at 2, ... ]
;B[np]
C[... Black defends at 3. Black now has mapped out territory at the top and the bottom. White is secure on the right, but her shape is depressed and small. <= ]
)
(;B[pg]
C[Failure.  

Black might feel good about securing his stones an the right ... ]
;W[pf];B[rh];W[qh];B[qi];W[rg];B[rj];W[sh];B[qk]
LB[ld:A]
C[... with the sequence to 9, but White has also become secure, so she can now aim to invade at A. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ec][dc][cd][cf][qf][rf][qd][qc][kr][nq][no][pr]
AB[dp][pd][pp][ed][fd][fc][jd][pc][pe][og][qh][kp][qq][pn]
LB[nq:1][kp:2][no:3][pn:4][pr:5][qq:6][kr:7]
C[Problem 143. Black to play.  

In this problem, the same joseki as in Problem 142 has been played. Where is the vital point for Black ? ]
(;B[nm]
TE[2]
C[Correct Answer.  

Black 1 is the focal point for building a moyo. ... ]
;W[fp];B[dn]
TR[kp]
C[... Black should be willing to sacrifice his marked stone to expand his moyo in the center. <= ]
)
(;B[gq]
C[Failure.  

Extending to  Black 1 is aimless. ]
;W[nm]
C[White jumps to 2 and Black no longer is able to make a moyo in the center. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][dc][ec][cf][qc][qd][qf][rf][fq]
AB[dp][pd][pp][ed][fd][fc][jd][pc][pe][og][qh]
LB[fq:1]
C[Problem 144. Black to play.  

This time White approaches the handicap stone in the lower left corner instead of the lower right. How should Black respond ? ]
(;B[jp]
TE[2]
C[Correct Answer.  

The pincer of Black 1 begins to map out a gigantic moyo in the right half of the board. ]
;W[dn]
C[If White makes another approach move at 2, ... ]
;B[en]
C[... Black attaches at 3. ]
;W[em];B[eo];W[cq];B[dq];W[cp];B[do];W[co];B[fm];W[dm];B[gn]
C[The joseki to 13 is a typical result. Black dominates the center and, in spite of White's three corners, he has a commanding lead. <= ]
)
(;B[cn]
C[Failure.  

Black 1 fails to take into account the whole board. ]
;W[dr];B[cq];W[iq]
C[White plays the joseki to 4 and establishes a position at the bottom. <= ]
)
)
(;
GM[1]
SZ[19]
AW[qc][qd][qf][rf][cd][cc][cf][dc][ec][fb][gb][gc][hb][ic]
AB[dp][pd][pp][dd][ed][fd][fc][hc][hd][gd][id][pc][pe][og][qh][jd]
C[Problem 145. Black to play.  

Black is thick, but he doesn't have any territory. White, on the other hand, has iron-clad territory in two corners. Where should Black play so as to best utilise his thickness ? ]
(;B[jp]
TE[2]
C[Correct answer.  

Making a sanren-sei at the bottom has a good feel to it. All of Black's stones are facing the center and working as one strategic force. ]
;W[jc];B[kc];W[kb]
LB[jc:2]
C[If White tries to break into Black's territory at the top with 2 and 4, ... ]
;B[lb]
LB[kc:3]
C[... Black crushes her to the edge with 3 and 5. <= ]
)
(;B[jc]
C[Failure.  

Black 1 is small. Black does get some territory at the top, but not much more than he got in the Correct Answer. ]
;W[jq]
C[White immediately establishes a beachhead at the bottom with 2 and Black's stones are not working together as efficiently as they were in the Correct Answer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][fc][ch][eh][el][er][ol][pm][qm][qn][qo][qp][qq]
AB[dp][pd][pp][cj][ej][cl][jp][pq][po][pn][om][nm][pl][pk]
LB[er:1]
C[Problem 146. Black to play.  

White plays a low approach with 1, aiming to disrupt Black's moyo at the bottom. How should Black respond ? ]
(;B[dq]
TR[er]

TE[2]
C[Correct Answer.  

Extending to Black 1 is a standard response to the low approach of the marked white stone. ]
;W[hq]
C[White responds by jumping lightly to 2 ... ]
;B[jq];W[ho]
C[... and 4, but ... ]
;B[gp]
C[... Black launches a severe attack ... ]
;W[hp];B[in];W[hn];B[im]
C[... with the sequence to 9. ]
;W[gl]
C[White's stones are still not secure and Black has expanded his moyo in the bottom right. Meanwhile, his territory on the lower left side is still intact and White must worry about her endangered stones. <= ]
)
(;B[fq]
C[Failure.  

Building thickness with the sequence from 1 ... ]
;W[fr];B[gq];W[cq];B[dq];W[dr];B[cp]
C[... to 7, ... ]
;W[bq];B[gi]
C[... then expanding the moyo with 9, is an interesting strategy, but ... ]
;W[jj]
C[... White 10 is the key point for wiping out  Black's moyo. White's gain in the corner is too big with respect to what Black can expect to gain from his moyo. Moreover, White can make incursions into Black's moyo on the left and the right from her corner. ]
)
)
(;
GM[1]
SZ[19]
AW[dd][ck][oh][pf][qf][lc][le]
AB[dp][pd][cn][po][qq][pi][qe][nd]
C[Problem 147. Black to play.  

The black stones in the upper right corner are nearly engulfed by the white stones. What should Black do ? ]
(;B[ob]
LB[qc:A]

TE[2]
C[Correct Answer.  

Black 1 is a move that you should remember. It is the best way for Black to secure the corner and eliminate all the bad aji of a white invasion at A. ]
;W[oi]
C[In response to White 2, ... ]
;B[pk]
C[... Black jumps lightly to 3. ]
;W[oj]
C[He then ignores White 4 and ... ]
;B[ci]
C[... invades the right side with 5. <= ]
)
(;B[mb]
LB[qc:B][ob:A]
C[Failure.  

Black 1 is an aggressive move which puts pressure on the top, but in this position it is not appropriate because there is nothing to attack. More important, it doesn't secure the corner because the bad aji of White A and B remains. <= ]
)
)
(;
GM[1]
SZ[19]
AW[dc][fd][nc][ob][qg][qj][cn][ci]
AB[dp][pd][pp][jd][oc][qe][ql][jq][fp]
C[Problem 148. Black to play.  

With the hane of 1, White threatens to uproot the black stones in the corner. Take a global view of the position before deciding on Black's response. ]
(;B[nd]
TE[2]
C[Correct Answer.  

This problem shows the importance of playing for thickness on the outside instead of defending the territory in the corner. Black plays on top with1 and ... ]
;W[md];B[mc];W[nb];B[lc];W[qc]
C[... lets White secure a small territory in the corner, ... ]
;B[me]
C[... but the thickness Black gets up to 7 strategically affects the whole board. ]
;W[pc];B[od]
C[<= ]
)
(;B[pb]
C[Failure.  

Defending the corner with Black 1 ... ]
;W[od]
C[... lets White force with 2. ]
;B[pc];W[lc]
C[She then occupies the key point of 4. ]
;B[ke]
C[If Black escapes into the center with 5, ... ]
;W[mf]
C[... White jumps to 6 and the two black stones at the top suddenly find themselves under attack. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][ec][dc][cf][qf][oh]
AB[dp][pd][pp][ed][fd][fc][jd][qh]
LB[oh:1]
TR[qh]
C[Problem 149. Black to play.  

Capping with 1 was an unorthodox response to the pincer of the marked stone. How should Black respond ? ]
(;B[pf]
TE[2]
C[Correct Answer.  

Black should take advantage of White's thin position and attach at 1. ]
;W[pe];B[oe];W[qe];B[pg];W[qd];B[pc];W[qc];B[qb];W[rb];B[pb];W[rg]
C[The sequence to 12 is almost inevitable. White lives in the corner, but ... ]
;B[nf]
TR[oh]
C[... Black gets a thick position in the top right when he connects at 13. The marked capping stone (White 1 in the Problem Diagram) is now cut off. <= ]
)
(;B[nd]
C[How the game continued.  

Although not as severe as the Correct Answer, Black 1 was also a good move, but, ... ]
;W[qi]
C[... when White attached with 2, ... ]
(;B[pi]
C[... Black 3 enabled White to secure her stones and ... ]
;W[ph];B[qj];W[ri];B[pj];W[rj];B[rk];W[qg]
C[... make a thick position with the sequence to 10. <= ]
)
(;B[ri]
C[Variation.  

Playing a hane with Black 3 would be better. ]
;W[pi]
C[White will draw back with 4 ... ]
;B[qj]
C[... and Black will play 5. ]
;W[pk]
C[White will probably play elsewhere, but, if she were to play around here, ... ]
;B[qk];W[pl];B[ql];W[pm];B[qm];W[pn]
C[... making thickness with the sequence to 12 gives her the best prospects. ]
;B[ro]
LB[qd:C][qc:B][pg:A]
C[If Black A, White will invade the corner with B, so Black C is the biggest point for Black in this position. <= ]
))
)
(;
GM[1]
SZ[19]
AW[cd][fq][op][mp][nq]
AB[dp][pd][qp][qn][pq][oq]
LB[fq:1]
C[Problem 150. Black to play.  

White 1 is an overplay. How should Black punish White ? ]
(;B[ip]
TE[2]
C[Correct Answer.  

Black should break up White's position at the bottom with the high invasion of 1. ]
;W[fo]
C[After exchanging 2 ... ]
;B[dn]
C[... for 3, ... ]
;W[in]
C[... White might cap wit 4, but ... ]
;B[lq]
C[... Black exchanges 5 ... ]
;W[mr]
C[... for White 6, ... ]
;B[ko]
C[... then jumps out into the center with 7. All of Black's stones are safe, but White is split into two weak groups. This should be an easy game for Black. <= ]
)
(;B[dn]
C[Failure.  

Black 1 is passive. You will never be able to win against a strong player on a two-stone handicap by playing this way. ]
;W[dr]
C[White exchanges 2 ... ]
;B[cq]
C[... for 3, ... ]
;W[iq]
TR[fq]
C[... then makes ideal shape with 4, which was the point she should have played instead of the marked stone in the Problem Diagram. <= ]
)
)
(;
GM[1]
SZ[19]
AW[bd][cd][bc][dc][db][ec][fb][gc][hc][qf][nq][jp]
AB[dp][pd][pp][dd][cc][be][ce][ed][fd][gd][fc][qj][pn][dj]
LB[qf:1]
C[Problem 151. Black to play.  

White approaches with 1. Where should Black play next ? ]
(;B[hq]
TE[2]
C[Correct Answer.  

White's stone on the right side is outnumbered, so playing there is not urgent. Instead, Black should extend to 1, aiming to play the sequence Black A - White B - Black C - White D - Black E. The white stones at the bottom would then be in disarray. <= ]
)
(;B[qe]
C[Failure.  

Black 1 ... ]
;W[pf];B[nc]
C[... and 3 are good moves that attack the white stone on the right, but ... ]
;W[cn]
LB[hq:A]
C[... White opens a new battlefield with 4. The fighting around will now be difficult, but, if Black had a stone at A, he would have a clear advantage. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][fc][nc][nb][pc][qc][qm][ro][qq][nq][mp][iq]
AB[dp][pp][lc][me][qd][pd][od][pj][oq][np][mq][no][dn][ci]
LB[cd:1][fc:11][lc:4][me:10][nb:9][nc:3][od:8][qc:5][qd:6][pc:7]
LB[pj:2][qm:21][ro:19][qq:17][oq:18][mq:20][np:14][no:16][mp:15][nq:13]
LB[iq:23][ci:12][dn:22]
C[Problem 152. Black to play.  

In this three-stone handicap game, White invades the bottom with 23. How should Black respond ? ]
(;B[gq]
TE[2]
C[Correct Answer.  

Black should make the checking extension of 1, ... ]
(;W[kq]
C[... forcing White to extend to 2. ]
;B[qp]
C[Black next plays the forcing sequence ... ]
;W[rp];B[qr];W[rr];B[pq]
C[... to 7, to give his stones on the right breathing room in case they get into trouble, ... ]
;W[rq];B[ho]
C[... then attacks White's group at the bottom with 9. <= ]
)
(;W[io]
C[Variation.  

If White jumps to 2, ... ]
;B[im]
C[... the cap of Black 3 is an interesting move. ]
;W[go]
C[If White tries to escape with 4, ... ]
;B[eq]
C[... Black will secure the territory at the bottom with 5. <= ]
))
(;B[kq]
C[How the game continued.  

Not only was Black 1 too narrow an extension, it was also the wrong direction. ]
;W[fq]
C[White was able to stabilise her stones at the bottom with 2 ... ]
;B[eq];W[fp]
C[... and 4. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][dc][ec][cf][qf][qg][ph][oh][qi][ri][rj]
AB[dp][pd][pp][fc][fd][ed][jd][nd][qh][pi][pj][qj][rk]
TR[qg]
C[Problem 153. Black to play.  

Where should Black play after White secures her position in the upper right with the marked stone ? ]
(;B[jp]
LB[qk:A]
TR[pi][pj][qj]

TE[2]
C[Correct Answer.  

The marked stones on the right side are heavy, so Black should take a bit point at the bottom with 1. This move even has the effect of defending the cut at A by making a ladder-blocking move at the bottom more difficult for White. Regardless, Black should be flexible enough to sacrifice the marked stones should that become necessary. The white stones above are settled, so Black has no prospects for attack by saving these stones. <= ]
)
(;B[ql]
C[How the game continued.  

Black made shape with 1, but ... ]
;W[jq]
C[... this gave White the chance to break up the bottom with 2. ]
;B[gq]
C[After Black made the checking extension of 3, ... ]
;W[qq]
C[... White took the corner with the sequence from 4 ... ]
;B[pq];W[qp];B[qr];W[rr];B[pr];W[qn]
C[... to 10. The game was becoming difficult for Black. <= ]
)
)
(;
GM[1]
SZ[19]
AW[ec][ic][ql][po][qp][ko][kp][kq][gq]
AB[dp][pd][cd][de][qr][oq][np][lp][iq][io]
LB[gq:1]
C[Problem 154. Black to play.  

White attacks the two black stones by invading at 1. How should Black respond ? ]
(;B[fp]
TE[2]
C[Correct Answer.  

Black should treat the two black stones at the bottom lightly and jump to 1. ]
;W[ir]
C[White can save the invading stone by attaching at 2, but this is quite small. Next, ... ]
;B[cj]
C[... Black takes the key point of 3 and all of his stones on the left side are working efficiently. <= ]
)
(;B[hp]
C[Failure.  

Preventing White from linking up by playing 1 is not good. ]
;W[fo]
C[White jumps to 2 and the three black stones become heavy. There is no comparison between this result and the one in the Correct Answer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][ce][cg][di][fd][gf][id]
AB[dp][pd][pp][eh][ef][de][dd][ec][kd]
LB[kd:6][id:3][fd:11][gf:7][ec:2][cd:1][dd:12][ce:9][de:8][ef:4]
LB[cg:5][eh:10][di:13]
C[Problem 155. Black to play.  

How should Black play after the sequence to White 13 ? ]
;B[cc]
TE[2]
C[Correct Answer.  

Black should settle his stones with the two-step hane of 1 ... ]
;W[bc];B[bb]
C[... and 3. ]
;W[cb]
C[If White takes the corner with 4 ... ]
;B[dc]
(;W[ab]
C[... and 6, ... ]
;B[cf]
LB[ab:6]
C[... Black wedges in at 7 and White is at a loss for a good move. Therefore White should not play 6. <= ]
)
(;W[bd]
LB[dc:5]
C[Variation.  

After Black connects at 5, White should connect at 6. ]
;B[ab]
C[Black can settle his stones in the corner by descending to 7. Next, ... ]
;W[kf]
C[... White must look after her stones at the top, so she caps with 4, but ... ]
;B[nd]
C[... Black just maps out territory in the upper right with 5. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][fc][nc][nb][pc][qc][qm][ro][qq][nq][mp][iq][fq][fp]
AB[dp][pp][lc][me][qd][pd][od][pj][oq][np][mq][no][dn][ci][kq][eq]
TR[fp]
C[Problem 156. Black to play.  

How should Black respond after White plays the marked stone (White 4 in the game continuation of Problem 152) ? ]
(;B[jo]
TE[2]
C[Correct Answer.  

The black stones at the bottom have bad aji, so Black should strengthen them by attacking the white group with 1 ... ]
;W[io];B[in]
C[... and 3. ]
;W[ho];B[cf]
C[He can then take the key point at 5 on the left side. <= ]
)
(;B[cf]
C[How the game continued.  

Black extended to 1 without strengthening his stones at the bottom, so ... ]
;W[jo]
C[... White took her opportunity to stabilise her stones there by playing 2. ]
;B[fr];W[gr];B[er];W[ck];B[cm];W[ek]
C[The game continued to White 8. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][dc][ec][cf][qf][qg][ph][oh][qi][ri][rj][jq][qn][qp][qq][rr]
AB[dp][pd][pp][fc][fd][ed][jd][nd][qh][pi][pj][qj][rk][gq][qr][pr][pq][ql]
TR[qn]
C[Problem 157. Black to play.  

White has just played the marked stone (White 10 in the game continuation of Problem 153). How should Black continue ? ]
(;B[qo]
TE[2]
C[Correct Answer.  

Wedging in with Black 1 is the tesuji. ]
;W[ro];B[po];W[pn];B[on];W[rm];B[om]
LB[rh:B][sj:A]
C[The sequence to Black 7 is inevitable. Because Black has the forcing exchange of Black A - White B, the white stones in the corner have bad aji. ]
;W[rs]
C[Therefore, White has to defend with 8 and Black ends in sente. <= ]
)
(;B[pn]
C[How the game continued.  

Attaching with Black 1 was a mistake. ]
;W[pm];B[qo];W[ro];B[po];W[qm];B[om];W[ol];B[nl];W[pl];B[nk];W[oj]
LB[om:7]
TR[qj][pi][pj]
C[White was able to make a big gain on the right with the sequence to 12. The three marked black stones still have some aji, but it is clear that Black has suffered a big loss compared with the Correct Answer. In addition, Black's wall has a defect since White can atari the stone at 7. <= ]
)
)
(;
GM[1]
SZ[19]
AW[de][dc][rd][qf][qi][nq][np][jp][jq][iq][fq][cn][cp][cq][cr][dr]
AB[dp][pd][pp][jc][nd][qc][qn][oq][ip][hp][hq][eq][er][dq][do][cg][cj]
LB[dc:3][de:1][cg:22][cj:10][cn:21][do:16][cp:15][cq:13][cr:19][dr:17]
LB[dq:14][fq:11][eq:20][er:18][hq:12][hp:28][ip:26][iq:25][jq:27][jp:29]
LB[np:31][nq:23][oq:30][qn:24][pp:2][jc:4][nd:6][qc:8][rd:7][qf:5]
LB[qi:9]
C[Problem 158. Black to play.  

After White stands at 31, how can Black take a decisive lead ? ]
(;B[jo]
TE[2]
C[Correct Answer.  

Black first builds influence in the center ... ]
;W[ko];B[kn];W[lo];B[ln];W[mn];B[mm]
C[... with the sequence to 7. ]
;W[nn];B[lq]
C[He then makes a placement at the vital point of White's shape with 9. ]
;W[lp]
C[White must defend with 10. ]
;B[nr]
C[Now Black can seal off the corner with 11 ... ]
;W[mr];B[or]
C[... and 13 ... ]
;W[mq]
LB[cm:B][em:A][kn:3][jo:1]
C[... in sente. Next, Black can aim at A, threatening to attach at B. However, he might first want to fix up his shape in the center by connecting between 1 and 3. <= ]
)
(;B[gc]
C[How the game continued.  

Black extended to 1 at the top and ... ]
;W[ql]
LB[jo:A][gc:1]
C[... White extended to 2 on the right side. These two points were miai, so Black 1 was not really urgent. However, with White now menacing the black stones in the lower right with 2, it is even more urgent that Black hanes at A and play the sequence in the Correct Answer. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][ce][cg][di][fd][gf][id][ig][jg][kg][md][lh][mi]
AB[dp][pd][pp][eh][ef][de][dd][ec][kd][gh][ih][jh][li][le][me]
LB[gh:1][ig:2][ih:3][jg:4][jh:5][kg:6][li:7][md:8][le:9][lh:10]
LB[me:11][mi:12]
C[Problem 159. Black to play.  

The game in Problem 155 continued with the sequence to the hane of White 12. How should Black continue ? ]
(;B[lj]
LB[jj:B][kh:A]

TE[2]
C[Correct Answer.  

Black should extend to 1, maintaining his dominance in the center. (If White A, Black makes shape with B.) ]
;W[od]
C[If White next switches to the top right by attaching at 2, ... ]
;B[pe];W[pc];B[qc];W[qb];B[oc];W[pb];B[nd];W[qd];B[oe];W[rd]
C[... Black can build a thick position and force White to live in the corner in gote with the sequence to 12. ]
;B[mj]
C[Black 13 is now a thick move, putting enormous pressure on the white stones at the top. <= ]
)
(;B[ki]
C[How the game continued.  

Black drew back with 1. This was passive because ... ]
;W[mj]
C[... it allowed White to take the initiative in the center with 2. ]
;B[nd]
C[Black secured the top with 3 and ... ]
;W[qd];B[qc];W[pe]
LB[qd:4]
C[... White made forcing moves with 4 and 6, ... ]
;B[pc];W[qn]
C[... then made an approach move at the bottom with 8. ]
;B[np]
C[White clearly covets the right side, although her stones there are, at the moment, a bit thin. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][fc][nc][nb][pc][qc][qm][ro][qq][nq][mp][iq][fq][fp][ck][ek][gr][jo]
AB[dp][pp][lc][me][qd][pd][od][pj][oq][np][mq][no][dn][ci][kq][eq][cm][fr][er][cf]
TR[ek]
C[Problem 160. Black to play.  

How should Black respond to the marked white stone (White 8 in the game continuation of Problem 156) ? ]
(;B[ei]
TE[2]
C[Correct Answer.  

Black should strengthen his stones in the upper left by jumping to 1. ]
(;W[gk]
C[If White jumps to 2, ... ]
;B[dd]
C[... Black can start moving against White's corner enclosure by attaching at 3 ... ]
;W[dc];B[cc]
C[... and cutting with 5. ]
;W[bd];B[bc];W[bb];B[ec];W[db];B[ed];W[eb];B[be];W[cb];B[ce];W[ac]
C[The sequence to White 16. where Black builds thickness by squeezing White, is inevitable. ]
;B[ge]
LB[gc:A]
C[Finally, Black perfects his shape with 17, threatening to attach at A. <= ]
)
(;W[ee]
C[Variation.  

If White defends her position in the upper left with 2, ... ]
;B[fk]
C[... Black can attach at 3. ]
;W[fl];B[gk];W[ej];B[fi];W[em];B[gl]
C[With the sequence to 9, Black has built thickness in the center. <= ]
))
(;B[fm]
C[How the game continued.  

Black jumped to 1, ... ]
;W[ei]
C[... letting White take the key point of 2. ]
;B[ef]
C[When Black jumped to 3, ... ]
;W[gf]
C[... White capped with 4, so ... ]
;B[bd];W[bc];B[be]
LB[bd:5]
C[... Black played 5 and 7 to make a base for his stones. ]
;W[de]
C[Next, White peeped at 8. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][dc][ec][cf][qf][qg][ph][oh][qi][ri][rj][jq][qn][qp][qq][rr][oj][ol][pl][pm][qm][ro]
AB[dp][pd][pp][fc][fd][ed][jd][nd][qh][pi][pj][qj][rk][gq][qr][pr][pq][ql][nk][nl][om][pn][po][qo]
TR[oj]
C[Problem 161. Black to play.  

How should Black attack the white stone at the bottom after White plays the marked stone ? ]
(;B[lq]
TE[2]
C[Correct Answer.  

Even though it is a bit close to Black's thickness, Black 1 is a powerful move. It denies the white stone a base and forces it out into the center where it is confronted by black thickness on the right and a stable position on the left. ]
;W[jo]
C[When White jumps out to 2, ... ]
;B[jm]
C[... Black caps with 3 and White is in trouble. <= ]
)
(;B[jo]
C[How the game continued.  

Black immediately capped with 1, but ... ]
;W[mq]
C[... this let make White make a base for her stones by extending to 2. ]
;B[lr];W[lq];B[kr]
LB[lr:3]
C[Next, Black tried to uproot the white stones with 3 and 5, but ... ]
;W[kq]
C[... these moves were not very good. <= ]
)
)
(;
GM[1]
SZ[19]
AW[de][dc][rd][qf][qi][nq][np][jp][jq][iq][fq][cn][cp][cq][cr][dr][ql]
AB[dp][pd][pp][jc][nd][qc][qn][oq][ip][hp][hq][eq][er][dq][do][cg][cj][gc]
LB[jo:A]
TR[gc][cg]
C[Problem 162. Black to play.  

Playing Black A, as in the Correct Answer to Problem 158, is best. However, with the marked stones in place, the two white stones in the upper left are vulnerable. If Black wants to attack them, what is the best way to do so ? ]
(;B[cd]
TE[2]
C[Correct Answer.  

The peep of Black 1 is the vital point. ]
(;W[dd]
C[If White connects with 2, ... ]
;B[ce]
C[... Black links up with 3 and ... ]
;W[cc]
C[... White must settle her stones with 4. ]
;B[jo]
C[Next, Black can hane at 5. <= ]
)
(;W[ce]
C[Variation.  

If White blocks with 2, ... ]
;B[be];W[bf];B[bd];W[cf];B[dd];W[ed];B[ec]
C[... Black cuts through with the sequence to 9. ]
;W[cc]
C[If White resists with 10 ... ]
;B[bc];W[bb]
C[... and 12, ... ]
;B[ee]
C[... Black forces with 13, ... ]
;W[fd];B[bg]
C[... 15, ... ]
;W[af];B[fe]
C[... and 17. ]
;W[gd];B[df]
C[After Black 19, the ladder starting with ... ]
;W[ef]
C[... White 20 - ... ]
;B[dg]
C[... Black 21 - ... ]
;W[ge]
C[... White 22 is unfavourable for  White, so her position collapses. <= ]
))
(;B[be]
C[How the game continued.  

Black slid to 1 and ... ]
;W[cd];B[bd]
C[... crawled to 3. Compared with the Correct Answer, Black did not get as much territory, so he doesn't get full marks for these moves. ]
;W[bc];B[cl]
C[Next, the exchange of Black 5 ... ]
;W[cm]
C[... for White 6 was bad for Black because it induced White to play 6, which strengthened her corner and diminished Black's influence in the center. See Problem 165. ]
)
)
(;
GM[1]
SZ[19]
AW[cd][ce][cg][di][fd][gf][id][ig][jg][kg][md][lh][mi][qd][pe][mj][qn][cf][df][cn][dm][en][ei]
AB[dp][pd][pp][eh][ef][de][dd][ec][kd][gh][ih][jh][li][le][me][nd][pc][qc][np][dg][gg][dn][do][co]
LB[cn:1][dn:2][dm:3][en:5][co:4][do:6][ei:7][gg:8][df:9][dg:10]
LB[cf:11]
C[Problem 163. Black to play.  

The game in Problem 159 continued to White 11. How should Black continue ? ]
(;B[fc]
TE[2]
C[Correct Answer.  

Since White's stones in the upper left are now strong, Black can no longer settle his stones in the corner as he did in the Correct Answer of Problem 155. Therefore, he should first exchange 1 ... ]
;W[gd]
C[... for 2, ... ]
;B[ee]
C[... then connect at 3. Black has substantial territory in the lower left and the top right, with prospects of making territory in the lower right, so he still has a good game. <= ]
)
(;B[ff]
C[How the game continued.  

Black played 1, needlessly risking a ko in the top left. ]
;W[ee];B[fc];W[gd];B[cc];W[bc];B[bb];W[cb];B[db];W[dc]
C[As it turned out, he didn't have enough ko threats, so he lost his group there. When you are in the lead, don't take risks like this. <= ]
)
)
(;
GM[1]
SZ[19]
AW[cd][fc][nc][nb][pc][qc][qm][ro][qq][nq][mp][iq][fq][fp][ck][ek][gr][jo][bc][de][gf][ei]
AB[dp][pp][lc][me][qd][pd][od][pj][oq][np][mq][no][dn][ci][kq][eq][cm][fr][er][cf][bd][be][ef][fm]
TR[de]
C[Problem 164. Black to play.  

White has peeped with the marked stone (White 8 in the game continuation of Problem 160). How should Black respond ? ]
(;B[df]
TE[2]
C[Correct Answer.  

Black 1 is a strong move. ]
;W[fh]
C[If White blocks Black's access into the center with 2, ... ]
;B[hc]
C[... Black 3 becomes a serious threat. ]
;W[jj]
C[That is, if White plays elsewhere (White 4 here is necessary to get 'Black to move"), ... ]
;B[dc];W[cc];B[db]
LB[dc:5][ee:A][fb:B]
C[... Black can destroy White's corner with 5 and 7. White can't capture the stones at 5 and 7 because the points A and B are miai. <= ]
)
(;B[eh]
C[How the game continued.  

Black attached with 1, but ... ]
;W[fh]
C[... this enabled White to strengthen her stones on the left side with 2 ... ]
;B[eg];W[di]
C[... and 4. ]
;B[ch]
C[Black drew back with 5 and ... ]
;W[cj]
C[...  White made shape with 6. Although White has strengthened her stones on the left, her stones at the top are still weak. Next ... ]
;B[ed]
C[The vital point.  

... Black can make a placement at 7. ]
;W[ee]
C[If White resists with 8, ... ]
;B[cc]
C[... Black cuts with 9 and ... ]
;W[dc];B[cb]
C[... wrests the corner away from White with 11. When a thick position faces a thin one as here, there is usually a tesuji that will give the thick one an advantage. <= ]
)
)
(;
GM[1]
SZ[19]
AW[de][dc][rd][qf][qi][nq][np][jp][jq][iq][fq][cn][cp][cq][cr][dr][ql][bc][cd][qo][ro][qq][en][em][cm]
AB[dp][pd][pp][jc][nd][qc][qn][oq][ip][hp][hq][eq][er][dq][do][cg][cj][gc][bd][be][pr][po][fp][cl][bl][dl]
LB[bl:1][dl:3][em:2][en:4][fp:5][qq:6][pr:7][qo:8][po:9][ro:10]
C[Problem 165. Black to play.  

After the sequence to Black 5 was played, White invaded the corner with 6. How should Black continue after White 10 ? ]
(;B[no]
LB[pn:B][rn:A]

TE[2]
C[Correct Answer.  

Black wants to block at A, but then White would cut at B. Therefore, Black leans on the white stones on the left by attaching with 1. ]
;W[mo]
C[If White 2, ... ]
;B[nn]
LB[pn:A]
C[... Black extends to 3. Now his defect at A is covered, so ... ]
;W[rn]
C[... White must turn at 4. ]
;B[mn]
C[Next, Black turns at 5 and attacks the white stones below ... ]
;W[lo];B[nr];W[mr];B[ln];W[kn];B[km]
C[... with the sequence to 11. ]
;W[jn];B[ok]
C[Finally, Black plays 13 and establishes a strong position in the center. <= ]
)
(;B[pn]
C[How the game continued.  

Black connected at 1, so ... ]
;W[rn]
C[... White turned at 2. ]
;B[nr]
C[After exchanging 3 ... ]
;W[mr]
C[... for White 4, ... ]
;B[nn]
C[... Black jumped to 5. ]
;W[ns]
C[White exchanged 6 ... ]
;B[or]
C[... for Black 7, ... ]
;W[jn]
C[... then jumped to 8. Now, instead of White being under attack as in the Correct Answer, the black stones on the right, and even the ones on the left, were under attack. The sequence in the Correct Answer is a good example of a leaning attack. That is, instead of defending a weak point directly, Black defended it by attacking another group. <= ]
)
)