(; GM[1] SZ[19] AW[dc][ce][ch][jd][mc] AB[cj][pc][qe] C[Problem 159. Black to play. The position is similar to the one in Problem 157. However, there are some differences. These differences should influence the way you erase White's moyo. ] (;B[hc] LB[he:B][jb:A] TR[jd] TE[2] C[Correct Answer. Since the marked stone is on the fourth line, light erasing moves such as caps or shoulder hits are not applicable. Black 1 is the perfect point because it aims at White's weak underbelly at A or a jump at B. ] (;W[he] C[That is, if White caps at 2, ... ] ;B[jb] (;W[kc];B[fc] LB[jb:3] C[... Black plays 3 and 5, taking profit while making a stable position. <= ] ) (;W[fc] C[If White 4 here, ... ] ;B[kc] LB[hc:1] C[... Black answers at 5. In any case, as long as there is room to expand, a deep invasion at 1 is possible. <= ] )) (;W[ic] C[Variation. White might attach at 2. ] (;B[he] C[In this case, Black jumps lightly to 3, escaping into the center. ] ;W[hb];B[gc];W[gb] LB[hb:4] C[Linking up to her stones at the top with 4 and 6 are big moves, but since White was strong here to begin with, this was to be expected. <= ] ) (;B[ec] C[However, Black can prevent White from linking up by exchanging 3 ... ] ;W[dd] C[... for 4, ... ] ;B[he] C[... then jumping to 5. ] ;W[hb] C[If White now plays 6, ... ] ;B[gc] C[... she can't link up after 7. <= ] ))) (;B[hd] C[Failure. Playing on the fourth line with 1 is bad. ] ;W[fc] C[White extends to 2 and Black's stone is without roots or follow-up moves. <= ] ) (;B[he] C[Failure. Erasing lightly with Black 1 is a failure. ] ;W[hc] C[White answers with 2, taking profit. <= ] ) )