(;
GM[1]
SZ[19]
AW[dd][dj][dp][jp][mp]
AB[op][pq][pk][pd][jd]
C[Problem 70. Black to play.  

All the big points have been taken, with both sides staking out their own moyos. Where should Black play next ? ]
(;B[pf]
TR[pk]

TE[2]
C[Correct Answer.  

Now is the time for Black to solidify his moyo. He should play 1 in the direction of the marked stone so as to strengthen the thinnest part of his position. <= ]
)
(;B[fc]
C[Failure.  

Expanding his moyo with 1 is certainly a good point, but ... ]
;W[qf]
C[... White will approach at 2. ]
;B[qe];W[pf];B[nd];W[qi]
LB[cd:B][cc:A]
C[With the sequence to White 6, Black's moyo has been erased. Black can aim at the invasion at A, but White would block at B and build a moyo along the left side. <= ]
)
)