(;AB[pc]AB[pe]AB[pf]AB[qf]AB[re]AB[qh]AW[pd]AW[qd]AW[rd]AW[qe]AW[oc]AW[ob]AW[nb]AW[mb]AW[ld]AB[nd]AB[od]AB[nc]C[Black to reduce white's corner]AP[goproblems]
(;B[rc];W[qc]
(;B[qb]
(;W[pb]C[CHOICE];B[sd];W[pc]C[RIGHT])
(;W[sd]C[CHOICE];B[pb];W[rb];B[sb];W[sc];B[ra]C[RIGHT]))
(;B[sd];W[qb]C[B can do better]))
(;B[qb];W[rf];B[rg];W[se]
(;B[rc];W[qc])
(;B[rb];W[rc];B[sc];W[pb];B[qc];W[qa]))
(;B[sd];W[rc]
(;B[rf];W[sc])
(;B[rb];W[sc];B[qc];W[se];B[rf];W[qb]))
(;B[qc];W[rc];B[rb];W[rf]))