(;
GM[1]
SZ[19]
AW[cc][dc][cd][ce][cg][rc][qc][pc][nc][nb][md][oi][ok][pp][qq][jq][dp]
AB[df][de][dd][ec][fd][lc][nd][od][pd][qd][rd][qk][pm][qo][qp][pq][oq]
TR[md]
C[Problem 72. Black to play.  

White has just played the marked stone. What should Black do ? ]
(;B[nh]
TE[2]
C[Correct Answer.  

Black should make a shoulder hit against the white stone on the right side. ]
(;W[ld]
C[If White follows up at the top with 2, ... ]
;B[mj]
C[... Black attacks with 3 ... ]
;W[om];B[ml]
C[... and 5. ]
;W[qj]
C[After the exchange of White 6 ... ]
;B[ql]
C[... for Black 7, White will have a hard time making life for her stones. <= ]
)
(;W[lj]
LB[nh:1]
C[Variation.  

If White responds to Black 1 by jumping to 2, ... ]
;B[mc]
C[... Black will cut at 3. ]
;W[me];B[jd]
TR[me][md]
C[Next, Black extends to 5, taking the territory at the top and leaving White's marked stones isolated from their allies below. <= ]
))
(;B[mc]
C[Failure.  

Immediately cutting with Black 1 is not good. ]
;W[me];B[jd];W[of];B[qh];W[jf]
C[White turns her stones in the center into a cohesive force with the sequence to 6. <= ]
)
)