(;
GM[1]
SZ[19]
AW[dc][gc][hc][ic][kc][kd][le][lf][lg][md][qn][pp][oq][cp][co][cm][cl][dj][di][kh][jh][jo]
AB[pd][pk][nq][nr][no][dq][dp][do][dm][ek][ce][fe][hd][id][jd][if][ke][kf][kg][lh][li][hp]
LB[jo:A]
TR[jh][kh]
C[Problem 93. Black to play.  

White, seemingly unable to decide how to play with his marked stones, makes a probe with A. How should Black attack ? ]
(;B[jm]
LB[qq:A]
TR[jo]

TE[2]
C[Correct Answer.  

Black should cap the marked stone with 1. This move isolates the two stones above. Although Black may not be able to capture this stone, he will be able to reinforce his position before going after the two stones above. In addition, he is aiming at the invasion of A. ]
;W[jq]
C[If White jumps down to 2, ... ]
;B[kp]
C[... Black will peep at 2. ]
(;W[jp]
C[Connecting at 4 is bad, because the three white stones are dead ... ]
;B[hq]
LB[qq:A]
C[... after Black 5. Black still aims at A. ]
)
(;W[ko]
C[White answered Black's peep with 3. This was a resourceful answer. ]
;B[jp];W[ip];B[io];W[iq];B[kq];W[ho];B[in];W[gp]
C[White was able to make sabaki with the sequence to 12. Next ... ]
(;B[gm]
C[Black 13 is a calm move. ]
;W[fq]
C[White must play at 14 to live, ... ]
;B[fi]
LB[qq:A]
C[... but Black 15 surrounds a vast framework of territory. Next, Black can aim to invade the lower right corner at A. Black has a won game. <= ]
)
(;B[fq]
C[Failure.  

After White 12, it is not a good idea to deprive White of a base with Black 13. ]
;W[gq];B[go];W[hn];B[hm];W[gn];B[fo];W[kr];B[lr];W[fn];B[fp];W[fl]
LB[qq:B][mp:A]
C[The sequence continues to 23, and White has escaped. Next, the peep of White A will be troublesome for Black, and takes away the value of an invasion at B. <= ]
)))
(;B[jq]
TR[jo]
C[Failure.  

Answering the marked stone with Black 1 is submissive. ]
;W[ho]
C[White will force with 2, ... ]
;B[gp];W[jk]
C[... then jump to 4. White should now have no trouble making two eyes within Black's sphere of influence. <= ]
)
)