(;
GM[1]
SZ[19]
AW[nc][nq][cq][dq][fq][cn][dm][hc][be][ed][db][eb][ec][fd][df][dh]
AB[pj][dj][dp][pd][pp][dd][pf][qm][ip][co][dn][en][fc][cm][bd][ce][de][ee][fe][dc][cb]
TR[dh]
C[Problem 71. Black to play.  

White has just played the marked stone (12 in Problem 67). How should Black respond ? ]
(;B[ci]
TE[2]
C[Correct Answer.  

Black 1 secures the lower left side and eliminates the bad aji there. It also deprives the three white stones in the upper left of a base, ... ]
(;W[gh]
C[... so White must escape into the center with 2. ]
;B[bg]
C[Next, Black slides to 3 and White no longer has any counterplay on the left side. It should now be an easy game for Black. <= ]
)
(;W[ch]
C[If White 2 here, ... ]
;B[fh]
C[... Black caps with 3. <= ]
))
(;B[kd]
C[How the game continued.  

Black invaded the top with 2, ... ]
;W[pc]
C[... so White settled her stones in the upper right ... ]
;B[qc];W[qb];B[qd];W[ob]
C[... with the sequence to 6. ]
;B[he]
C[The black stone at the top was now vulnerable, so Black reached out to it with 7, a move which also affected the white stones in the upper left. ]
;W[cj]
C[White switched to the left side with 8 and ... ]
(;B[ck];W[cl]
TR[cn][dm]
C[... the aji of the marked stones came to life when White ataried with 10. See Problem 75 for the continuation. <= ]
)
(;B[dk]
LB[ck:@]
C[Black 9 here, building a thick wall towards the center, would have been better than @. <= ]
))
)