(;
GM[1]
SZ[19]
AW[ed][gf][kd][nd][nc][pp][po][pq][oq][or][kp][cq][cr][dp][do][dj]
AB[dc][cd][df][if][id][oc][pd][pf][pr][qr][qq][qn][qp][nq][dq][eq]
TR[ed][gf]
C[Problem 89. Black to play.  

How should Black attack the two marked stones ? ]
(;B[hh]
TE[2]
C[Correct Answer.  

Attacking with the knight's move of Black 1 is the correct direction. ]
;W[gh];B[gi];W[fh];B[hi];W[dh]
C[After White 6, ]
;B[ic]
LB[fe:A]
C[... Black makes an iron pillar at 7, aiming at A as well as the three white stones on the right. <= ]
)
(;B[ei]
C[Failure.  

Black 1 is not a good move because it doesn't have a good follow-up. ]
;W[hg]
C[After White escapes into the center, ... ]
;B[ej]
C[... Black exchanges 3 ... ]
;W[dl]
C[... for 4, ... ]
;B[ek]
C[... then extends to 5. ]
;W[ig]
TR[id][if]
C[White extends to 6 and the two marked stones are under siege. ]
;B[dk]
LB[jf:A]
C[If Black tries to press his advantage on the left side, White can take control of the top with A. <= ]
)
)