(;
GM[1]
SZ[19]
AW[dc][pb][qb][qc][qd][qf][qg][nc][ne][ng][dq][cn]
AB[eb][fd][de][be][ob][oc][pc][pd][pe][pf][pg][nd][pp]
LB[nd:A]
C[Problem 125. White to play.  

Black wedges in with A. What should White do ? ]
;W[md]
LB[nd:A]

TE[2]
C[Correct Answer.  

Answering Black A with the atari of White 1 is obvious, but ... ]
;B[mc]
C[... White must be careful when Black cuts with 2. ]
(;W[lc]
C[White 3 ... ]
;B[nb];W[mb]
C[... and 5 are the best moves. ]
;B[me];W[ld];B[nf];W[mf];B[oe]
C[The sequence continues to Black 10. ]
;W[lf]
LB[le:A]
C[Here White 12 is the strongest move. White gets an excellent result because Black has gained absolutely no territory, while White has built a thick position on the outside. Later, if White gets to play A, Black might have a hard time to get two eyes. <= ]
)
(;W[nb]
LB[mc:2]
C[Failure.  

Answering the cut of Black 2 by descending to 3 might be good in some situations, but here ... ]
;B[mb];W[na];B[od];W[oa];B[qe];W[re];B[qh];W[rd];B[rh];W[rg];B[sg];W[rf];B[oi]
C[... Black gets a good position on the outside with the sequence to 15. ]
;W[lc]
C[Just like the Correct Answer, White has a strong position in the top right, but here, Black's stones on the right side are secure and work well with his stone in the lower right corner. <= ]
)
)