(;
GM[1]
SZ[19]
AW[dd][qj][dq]
AB[pp][qd][oc]
TR[qj]
C[Problem 56. Black to play.  

How should Black respond after White plays her marked stone ? ]
(;B[do]
LB[co:A]

TE[2]
C[Correct Answer.  

It is best for Black to make an approach move at 1 or A to prevent White from making a corner enclosure. ]
;W[co]
C[If White attaches at 2, ... ]
;B[cn];W[cp];B[dm];W[fq];B[ci]
C[... the joseki to 7 will follow. ]
;W[cg]
C[Attacking Black's formation on the left with White 8 is now the most reasonable move. <= ]
)
(;B[co]
TE[2]
C[Correct Answer.  

Also correct. <= ]
)
)