(;
GM[1]
SZ[19]
AW[cf][ch][ci][oi][pi][qi][rk][qg][jc][ld][md][nc][oc][pb][pe][qe][re][rd]
AB[cd][dd][df][dh][dp][pp][pj][oj][nj][ni][pg][nf][me][hc][he][qb][rc][pc][qd][pd][od][nd]
C[Problem 44. Black to play.  

White's stones at the top right are struggling for life inside Black's sphere of influence. How should Black attack them ? ]
(;B[lb]
TE[2]
C[Correct Answer.  

This is the kind of position in which you want to gauge out the eyes of your opponent's stones. The placement of Black 1 robs the white stones of their base and threatens to cut. White's stones are trapped inside Black's sphere of influence. Next ... ]
(;W[mb]
C[If White defends against the cut with 2, ... ]
;B[kc]
C[... Black links up with 3 ... ]
;W[kd];B[jb]
C[... and 5. White is without eyes, so she must seek life in the center. <= ]
)
(;W[kb]
C[Variation.  

White 2 here is another possibility, but ... ]
;B[nb]
C[... Black takes profit with 3 ... ]
;W[mb];B[ob]
C[... and 5. ]
;W[mc];B[ib]
C[After Black 7, White's group still doesn't have two eyes. <= ]
))
(;B[ib]
C[Failure.  

Black 1 ... ]
;W[jb];B[ob]
C[... and 3 are certainly sente, but ... ]
;W[nb]
C[... so is White 4, ... ]
;B[pa];W[lb]
C[... so White can secure two eyes with 6. <= ]
)
)