(;
GM[1]
SZ[19]
AW[dd][fc][kc][ld][nc][pb][jl][io][ko][dp][eq][fr][cn][di][pm][qp]
AB[pd][qc][pf][lf][je][pk][ll][kq][ip][hp][fp][fq][gr][op][pq][qq]
TR[pm][qp]
C[Problem 52. Black to play.  

The two marked stones are not very strong, but they still have some aji. How should Black attack them ? ]
(;B[qk]
TE[2]
C[Correct Answer.  

Black 1 forces the white stones to escape ... ]
;W[nm]
C[... with 2, but ... ]
;B[ln]
C[... Black prevents them from linking up with 3 ... ]
;W[no];B[lo]
C[... and 5. ]
;W[oo]
C[White tries to make shape with 6, but ... ]
;B[qn]
C[... Black 7 leaves White's stones eyeless within Black's sphere of influence. <= ]
)
(;B[nl]
C[Failure.  

Black 1 looks like a strong move, which builds a moyo in the center, but ... ]
;W[qk]
C[... this gives White the chance to attach with 2. ]
;B[qj]
C[If Black 3, ... ]
;W[rj]
C[... White hanes with 4 and she will easily be able to make sabaki. <= ]
)
)