(;
GM[1]
SZ[19]
AW[dd][dj][dp][fp][gp][hq][iq][pb][nc][kc]
AB[gq][hp][ho][jp][jq][pq][po][pk][pf][pd][qc][je]
LB[je:1]
C[Problem 171. White to play.  

Black has played 1. This is not such a good move. How should White counter it ? ]
(;W[ld]
TE[2]
C[Correct Answer.  

Although it may seen strange, White 1 is the correct response. You might want to make a more aggressive move to erase the black moyo, but White must be patient. You have to make your base strong before launching an all-out attack. ]
(;B[lf]
C[In order to prevent an intrusion into his moyo, Black drops back to 2. ]
;W[kf]
C[However, because the ladder is favourable for White, 3 is a sever tesuji. ]
;B[ke];W[le];B[lg]
C[Black must extend to 6, but ... ]
;W[kg];B[kh];W[if]
LB[kg:7]
C[... then 7 and 9 are powerful moves, challenging Black to a fight he cannot win. <= ]
)
(;B[jc]
C[Variation.  

If Black attaches at 2, ... ]
;W[jb];B[ic];W[ib]
LB[jb:3]
C[... White plays 3 and 5. ]
;B[gc]
C[After Black 6, ... ]
;W[lf]
C[... White punches a big hole in Black's moyo with 7. It's hard to say which side has the more favourable position, but at least White has as much chance as Black of winning. <= ]
))
(;W[id]
C[Failure.  

White 1 is a losing move. ]
;B[ld];W[lc];B[nd]
LB[ld:2]
C[Black plays 2 and 4 in sente, mapping out a huge moyo in the center. ]
;W[oc]
LB[cc:A]
C[Next, Black can aim at invading the 3-3 point with A, so White's territory at the top is not so big. It is clear that White is the big loser in this exchange. <= ]
)
(;W[ke]
TE[2]
C[Correct Answer.  

For reference, let's look at another way White could answer Black's erasure move. Against White 1, ... ]
;B[kd];W[ld];B[jd]
LB[kd:2]
C[... Black responds with 2 and 4. ]
;W[jc];B[jg];W[le];B[hd]
C[After Black jumps to 8, ... ]
;W[lg]
C[... White can also jump to 9. Black's position is not good. However, the moves in the Correct Answer are much clearer. <= ]
)
)