(;
GM[1]
SZ[19]
AW[dd][dp][jp][pf][qf][pi]
AB[pq][pk][jd][nd][pd][qe]
LB[pi:1]
C[Problem 87. Black to play.  

This time White defends with the extension of 1 on the fourth line. How should Black respond ? ]
(;B[mp]
TE[2]
C[Correct Answer.  

Black 1 is a flexible move. It defends against a white approach move. <= ]
)
(;B[nk]
C[Failure.  

If Black jumps to 1, ... ]
;W[ni]
C[... White will also jump to 2. It is better for Black to defer this defence until later because, since White's stone on the upper right is high, she has no good way to invade on the side. <= ]
)
)