(;
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. <= ]
)
)