(;
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. <= ]
)
)