(;
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. <= ]
)
)