(;AB[oa]AB[na]AB[ob]AB[oc]AB[pd]AB[qd]AB[rd]AB[sd]AB[re]AB[pe]AW[oe]AW[of]AW[qe]AW[qf]AW[rf]AW[sf]AW[se]AB[pf]AW[pg]AW[og]AW[od]AW[nc]AW[nb]AW[ma]AW[lb]AW[qb]C[What is the best black can do?]AW[qg]AP[goproblems] (;B[qc];W[pa] (;B[pb];W[pc]) (;B[pc];W[rb] (;B[sb];W[rc] (;B[pb];W[sc]) (;B[sc];W[pb]) (;B[ra];W[pb]) (;B[qa];W[pb])) (;B[pb];W[qa] (;B[sc];W[sb]) (;B[sb];W[rc])) (;B[qa];W[pb])) (;B[rb];W[pc] (;B[pb];W[pc] (;B[ra];W[sc]) (;B[sb];W[ra])) (;B[ra];W[sc] (;B[sb];W[rc]) (;B[rc];W[sb]) (;B[qa];W[pb]) (;B[pb];W[pc])) (;B[sb];W[ra]) (;B[sc];W[ra] (;B[sa];W[sb]C[ko, but white takes first, white has a local threat at Q18 and if black wins the ko, he still loses part of his group.]) (;B[pb];W[pc];B[sa];W[sb]C[Two stage ko.]))) (;B[sb];W[pc] (;B[pb];W[pc]) (;B[rb];W[ra]) (;B[ra];W[rb]))) (;B[pb];W[qc] (;B[rb];W[pc] (;B[rc];W[pa]) (;B[qa];W[pa])) (;B[rc];W[pc]) (;B[pc];W[sb] (;B[rc];W[rb] (;B[qa];W[ra]) (;B[ra];W[qa])) (;B[sc];W[rb]) (;B[qa];W[ra];B[rc];W[rb]) (;B[ra];W[qa] (;B[rc];W[rb]) (;B[rb];W[rc] (;B[sc];W[pa]) (;B[pa];W[sc])) (;B[sc];W[rc])) (;B[rb];W[rc] (;B[qa];W[ra]) (;B[sc];W[ra]) (;B[ra];W[qa] (;B[sc];W[pa]) (;B[pa];W[sc])))) (;B[qa];W[pc] (;B[pa];W[ra]) (;B[rb];W[pa]) (;B[rc];W[rb]))) (;B[rb];W[pc] (;B[qc];W[pb] (;B[sc];W[ra] (;B[sa];W[sb]C[ko, but white takes first, white has a local threat at Q19 and if black wins the ko, he still loses part of his group.]) (;B[qa];W[pa])) (;B[ra];W[sc]) (;B[sb];W[ra]) (;B[qa];W[pa] (;B[sc];W[ra]) (;B[ra];W[sc]) (;B[sb];W[ra]))) (;B[qa];W[pa] (;B[qc];W[pb] (;B[ra];W[sc]) (;B[sb];W[ra]) (;B[sc];W[ra])) (;B[pb];W[pa]) (;B[ra];W[pb] (;B[rc];W[sb]) (;B[sb];W[rc]) (;B[qc];W[sc]))) (;B[ra];W[pa] (;B[qc];W[sc] (;B[sb];W[rc]) (;B[rc];W[sb]) (;B[qa];W[pb]) (;B[pb];W[pc])) (;B[sb];W[rc] (;B[sc];W[qc]) (;B[qc];W[sc])) (;B[rc];W[sb])) (;B[sb];W[ra];B[qc];W[pb]) (;B[sc];W[qc];B[qa];W[pa]) (;B[pb];W[pa])) (;B[rc];W[pc]) (;B[pc] (;W[rc] (;B[sb] (;W[rb];B[sc]) (;W[sc] (;B[rb]) (;B[qc];W[rb]))) (;B[sc];W[sb] (;B[qc];W[rb]) (;B[rb];W[ra]) (;B[qa];W[ra])) (;B[qc];W[rb]) (;B[qa];W[ra] (;B[sc];W[sb]) (;B[sb];W[sc])) (;B[rb];W[sb] (;B[sc];W[ra]) (;B[qc];W[ra]) (;B[ra];W[qa] (;B[sc];W[qc]) (;B[qc];W[sa];B[rb];W[ra];B[sc]))) (;B[ra];W[qa] (;B[rb];W[qc] (;B[sb];W[sc]) (;B[sc];W[sb])) (;B[sc];W[sb];B[rb];W[qc]) (;B[qc];W[rb] (;B[sb];W[sc]) (;B[sc];W[sb])) (;B[sb];W[sc]))) (;W[rb];B[sb]) (;W[sb]C[CHOICE] (;B[rb];W[rc] (;B[ra];W[qa] (;B[qc];W[sa] (;B[rb] (;W[ra];B[sc]C[RIGHT]) (;W[sc];B[ra])) (;B[sc];W[rb])) (;B[sc];W[qc])) (;B[sc];W[ra]) (;B[qa];W[ra]) (;B[qc];W[ra]C[Black dies.])) (;B[rc];W[rb]) (;B[qa];W[ra]) (;B[ra] (;W[qa];B[rb];W[rc] (;B[sc];W[qc]) (;B[qc];W[sa] (;B[sc];W[rb]) (;B[rb] (;W[ra];B[sc]C[RIGHT]) (;W[sc];B[ra])))) (;W[rb];B[qa])) (;B[qc];W[rb]))) (;B[ra];W[pc] (;B[pa];W[qa] (;B[qc];W[pb];B[rb];W[sc]) (;B[rb];W[pb] (;B[sb];W[rc]) (;B[rc];W[sb]) (;B[sc];W[qc]) (;B[qc];W[sc]))) (;B[qa];W[pa] (;B[pb];W[pa]) (;B[qc];W[pb];B[rb];W[sc]) (;B[rb];W[pb] (;B[qc];W[sc]) (;B[rc];W[sb]) (;B[sb];W[rc]))) (;B[rb];W[pa] (;B[sb];W[rc] (;B[sc];W[qc]) (;B[qc];W[sc])) (;B[rc];W[sb]) (;B[qc];W[sc] (;B[sb];W[rc]) (;B[rc];W[sb]) (;B[pb];W[pc])))) (;B[pa];W[pc] (;B[qc];W[pb];B[rb];W[qa] (;B[sb];W[ra]) (;B[ra];W[sc]) (;B[sc];W[ra])) (;B[rb];W[qa] (;B[qc];W[pb] (;B[ra];W[sc]) (;B[sb];W[ra]) (;B[sc];W[ra])) (;B[ra];W[pb] (;B[sb];W[rc]) (;B[rc];W[sb]) (;B[sc];W[qc]) (;B[qc];W[sc])))) (;B[qa];W[pc] (;B[pb];W[pa]) (;B[pa];W[ra]) (;B[qc];W[pb] (;B[pa];W[ra]) (;B[rb];W[pa] (;B[sc];W[ra]) (;B[sb];W[ra]) (;B[ra];W[sc]) (;B[sa];W[sc]))) (;B[rb];W[pa] (;B[pb];W[pa]) (;B[qc];W[pb] (;B[ra];W[sc]) (;B[sa];W[sc]) (;B[sb];W[ra]) (;B[sc];W[ra]))) (;B[ra];W[pa] (;B[qc];W[pb];B[rb];W[sc]) (;B[pb];W[pa]) (;B[rb];W[pb] (;B[sb];W[rc]) (;B[sc];W[qc]) (;B[rc];W[sb]) (;B[qc];W[sc])))))