(;
GM[1]
SZ[19]
AW[dd][cg][co][cp][dq][fq][qj]
AB[ci][dm][cn][do][pp][qd][oc]
TR[cg]
C[Problem 60. Black to play.  

The marked white stone threatens to invade the black formation on the left side. Should Black defend against this threat or is there something else he should do ? ]
;B[qh]
TR[cg]

TE[2]
C[Correct Answer.  

Instead of defending against the marked stone, Black should start operations against the white stone on the right by extending from his corner enclosure above with 1. ]
;W[qm]
(;B[mq]
(;W[rp]
C[The sequence to 4 is the best continuation. <= ]
)
(;W[jc]
C[If White 4 here, ... ]
;B[qo]
C[... Black 5 takes the corner territory while attacking the white stones above. <= ]
))
(;B[jc]
C[Failure.  

Black must not rush to play the big point at the top with 3. ]
;W[nq]
TR[pp]
C[White will take the initiative at the bottom by playing a double approach against the marked black stone with 4. <= ]
)
)