(;
GM[1]
SZ[19]
AW[dd][df][dj][dp][hq][ho][jo][qp][qq][rq][sp][ro][rn][pn][qn][sn][nm][rm][pc][ob]
AB[jq][pq][pp][po][qo][on][om][ol][pm][qm][ql][rl][pd][oc][fc][jd][pf][lp]
LB[ob:A]
C[Problem 98. Black to play.  

What should Black do when White hanes at A ? ]
(;B[od]
TE[2]
C[Correct Answer.  

Connecting at Black 1 is the joseki move. ]
(;W[qc];B[nb];W[re];B[rf];W[qe];B[qf];W[pb]
C[White lives in the corner with the sequence to 8, but ... ]
;B[mc]
C[... Black gets a massive moyo when he connects at 9. <= ]
)
(;W[pb]
C[Variation.  

Connecting at 2 is also a joseki move. ]
;B[nb];W[qd];B[qe];W[rd];B[mc]
LB[rb:A]
C[After 7, Black's moyo is almost as large as in the Correct Answer. White has an opening into Black's moyo in the upper right, but this is compensated for by the bad aji White has if Black plays at A. (See Get Strong at Life and Death, Problem 101.) <= ]
))
(;B[pb]
C[Failure.  

The atari of Black 1 is also a joseki move, but, ... ]
;W[qc];B[qb];W[od];B[nc];W[nb];B[rb];W[qd];B[pe];W[mc];B[nd];W[me];B[ne];W[nf];B[md];W[ld];B[oe]
(;W[le]
LB[lb:A]
C[... after the sequence to White 18, Black's moyo has been drastically reduced. Instead of 18, White could also play A. ]
;B[lc]
C[The atari of Black 9 is small. ]
;W[kc]
(;B[mb];W[lb];B[mc];W[kd]
C[Moreover, Black's stones at the top left are weakened after White connects at 6. <= ]
)
(;B[lb]
C[Black might be able to get more profit by descending to 21, ... ]
;W[kd];B[mb]
C[... then capture with 23, ... ]
;W[je]
C[... but the two black stones at the top left are even weaker than in the preceding diagram after White 24. <=: ]
))
(;W[lb]
LB[le:@]
C[If White chooses to defend at 18, instead of @, ... ]
;B[le]
C[... Black can increase the size of his moyo by cutting at 19. ]
;W[ke]
C[White will then atari at 20 ... ]
;B[lf];W[kd]
LB[jc:A]
C[... and connect at 22, aiming next to play A. Black gets a moyo, but at the expense of weakening his two stones at the top. <= ]
))
)