(;
GM[1]
SZ[19]
AW[cd][ec][co][ck][kq][nq][qi]
AB[cp][do][dq][fp][pp][pn][pd]
LB[qg:B][qk:C][jc:A]
C[Problem 124. Black to play.  

White has played in the middle of the right side. Should Black ignore this move and extend to A, of should he attack White with a move at B or C ? ]
(;B[qk]
TE[2]
C[Correct Answer.  

Attacking the white stone with 1, driving it toward the star-point stone above, is best. ]
;W[qf]
C[White will extend to 2. ]
;B[qe];W[pf];B[nc]
C[The sequence to 5 is a joseki. <= ]
)
(;B[jc]
C[Failure.  

If Black extends along the top, ... ]
;W[ql]
C[... White will make a two-space extension down the right, attacking the black stones below. <= ]
)
(;B[qg]
C[Failure.  

Black 1 is the wrong direction. ]
;W[ql]
LB[qm:A][pl:B]
C[White plays 2, aiming at Black's weak underbelly. The exchange of Black A - White B strengthens White, so it is not good. ]
;B[oc]
C[If Black defends his corner at the top, ... ]
;W[kd]
C[... White makes a double-wing formation in the upper left with 4. <= ]
)
)