(;AP[goproblems]AW[ri]AW[rh]AW[qg]AW[pg]AW[og]AW[ng]AW[of]AW[rf]AW[qe]AB[re]AB[rd]AB[qc]AB[pd]AB[oc]AB[oe]AW[ne]AW[nd]AW[nc]AW[mb]AW[ob]AW[pb]AW[qb]AW[rb]AW[lb]AB[mc]AB[md]AB[me]AB[mf]AB[nf]AB[mg]AB[mh]AB[nh]AB[oh]AB[ph]AB[qh]AB[qi]AB[qj]AB[rj]AB[rk]AB[od]AW[nb]AW[pe]AB[sf]AW[rg]AB[qd]AW[pf]AB[si]C[What must white do now?](;W[sh];B[sj](;W[rc]C[RIGHT])(;W[pc]C[RIGHT])(;W[sc];B[se](;W[rc];B[sg])(;W[sd];B[sg])(;W[pc];B[sg]))(;W[sd];B[se](;W[sc];B[sg])(;W[rc]C[RIGHT])(;W[pc]C[RIGHT]))(;W[se]C[RIGHT]))(;W[sg];B[sd]LB[sj:A]LB[sh:B]C[Next, black will play A and B and the position will be ko])(;W[se];B[sh];W[sg];B[sj]C[This will end only in ko])(;W[sj];B[sk](;W[sh];B[se]C[This will be ko])(;W[sg];B[sd]C[White will have to play ko to capture black]))(;W[rc];B[sh]C[Whtie is captured])(;W[pc];B[sg]C[Whtie is captured])(;W[sd];B[sg]C[Whtie is captured]))