(;
GM[1]
SZ[19]
AW[cn][fm][dg][gg][hd][jj][im][nd][ne][nf][nh][jh][kb][lc][kd][ke][le][md]
AB[jp][jd][pj][dj][dp][pd][pp][dd][fd][fj][hj][fb][pg][lh][jf][je][jc][kc][me][mf][lf][kf][fp]
TR[im]
C[Problem 19. Black to play.  

The game in Problem 15 eventually reached this position. White has just played the marked stone, threatening to engulf the three black stones. How should Black respond ? ]
(;B[hh]
TE[2]
C[Correct Answer.  

Black should first exchange 1 ... ]
;W[hg]
C[... for White 2, ... ]
;B[fg]
C[... then attach with 3. ]
;W[ff]
C[If White 4, ... ]
;B[ef]
C[... Black hanes with 5. ]
(;W[eg]
C[If White next ataris with 6, ... ]
;B[fh]
C[... Black draws back with 7. <= ]
)
(;W[fh]
C[If White 6, ... ]
;B[eg];W[eh];B[gh]
C[... the sequence to Black 9 follows. In either case, White's stones are in tatters. Even if she manages to save one group, the other will die. <= ]
))
(;B[ch]
C[How the game continued.  

Black tried to live on the side with 1 ... ]
;W[cg];B[dh]
C[... and 3. This is usually a bad decision in an open position such as this because White can strengthen her stones and this will have a negative impact on the black stones in adjacent areas. ]
;W[eg]
C[In this game, White strengthened her stones with 4, denying Black the chance to cut through and link up to the top. ]
;B[fh];W[eh]
C[White 6 ... ]
;B[ei];W[bh]
C[... and 8 gave Black bad shape. ]
;B[bi]
C[If Black 9 next, ... ]
;W[bf]
C[... White will connect loosely with 10. ]
;B[cj]
C[Black must fix up his shape with 11, so ... ]
;W[cc]
C[... White can live and destroy Black's territory in the corner by jumping to 12. <= ]
)
)