(;
GM[1]
SZ[19]
AW[pg][nq][pn][om][pl][lj][mm][pq][qq]
AB[pj][dj][dp][pd][pp][dd][jj][mc][jq][on][oo][nj][mk][mp][qp]
LB[nj:1][lj:2][mk:3][mm:4]
C[Problem 78. Black to play.  

The game in Problem 74 continued with the sequence to White 4. How should Black respond ? ]
(;B[mq]
TE[2]
C[Correct Answer.  

Black's stones in the lower right are a bit thin, but Black can attack White and thicken his stones by blocking at 1. ]
;W[np]
LB[or:A]
C[White must defend against the peep of Black A, ... ]
;B[no];W[mr];B[lr]
(;W[nr]
C[... so he plays the sequence to White 6. ]
;B[mn];W[lm];B[lk]
C[The sequence continues to Black 9 and White has a hard fight ahead of her in trying to save her group in the lower right. <= ]
)
(;W[mo]
C[If White cuts at 6, ... ]
;B[nr]
C[... Black will cut at 7.) <= ]
))
(;B[lk]
C[How the game continued.  

Black defended his stones in the middle with 1, but this left the black stones below unsettled. ]
;W[ln]
C[White attacked with 2 ... ]
;B[lo]
C[See Problem 82 for the way Black should have answered White 2. ]
;W[ko]
C[... and 4, ... ]
;B[lp];W[lr]
C[... then defended by sliding to 6. ]
;B[kq];W[ip]
C[After White 8, the nine black stones were just a long thin string, without any eye-making potential. ]
)
)