(;
GM[1]
SZ[19]
AW[cd][dc][gc][di][fi][pq][mq][pk]
AB[ce][fe][dm][dp][qo][no][pd][pg]
TR[cd]
C[Problem 66. Black to play.  

White has attached with the marked stone, hoping to put the two black stones under siege. How should Black counterattack ? ]
(;B[ed]
TE[2]
C[Correct Answer.  

Black should play the forcing moves of 1 ... ]
;W[ec];B[bd];W[bc];B[he]
C[... to 5. ]
;W[id]
C[After White 6, ... ]
;B[hi]
C[... Black caps with 7 and the two white stones on the left side are under attack. <= ]
)
(;B[de]
C[Failure.  

Answering the attachment of the marked stone by standing at 1 here leaves the black stones heavy. ]
;W[ed]
C[White peeps with 2 and ... ]
;B[ee];W[hd];B[hg];W[hi];B[he];W[jd]
C[... the black stones are under attack after White 8. <= ]
)
)