(;AB[se]AB[re]AB[qe]AB[pd]AB[oc]AB[ob]AB[oa]AB[oe]AW[pc]AW[pb]AW[qa]AW[rc]AW[rd]C[Black to kill]AP[goproblems]
(;B[qd];W[qc]
(;B[rb];W[sb]
(;B[ra];W[sd];B[pa]C[Collect. White can't play R18.RIGHT]TR[qb])
(;B[sd];W[ra]))
(;B[sd];W[rb])
(;B[sb];W[rb]))
(;B[rb];W[sb]
(;B[ra];W[qb]
(;B[sd];W[qd])
(;B[qd];W[sd])
(;B[pa];W[sa])
(;B[qc];W[qd]))
(;B[qc];W[qb]
(;B[qd];W[ra])
(;B[sc];W[ra])
(;B[sd];W[ra])
(;B[pa];W[ra])
(;B[ra];W[qd]))
(;B[qb];W[ra])
(;B[sc];W[sd]
(;B[qb];W[qc])
(;B[qc];W[qb];B[qd];W[ra])
(;B[qd];W[qc]
(;B[ra];W[qb])
(;B[pa];W[ra])))
(;B[sd];W[ra])
(;B[qd];W[ra]))
(;B[sb];W[rb]
(;B[pa];W[qb]
(;B[qd];W[sa];B[ra];W[sc])
(;B[sd];W[sc]))
(;B[sc];W[sd]))
(;B[sd];W[rb])
(;B[sc];W[rb]
(;B[sd];W[sb])
(;B[sb];W[sd]))
(;B[qc];W[qd]
(;B[rb];W[sb]
(;B[sc];W[qb]
(;B[sd];W[ra])
(;B[sa];W[ra]))
(;B[sd];W[qb]))
(;B[sc];W[rb];B[sd];W[sb]))
(;B[pa];W[rb]
(;B[qc];W[qb];B[qd];W[sa])
(;B[sd];W[qd])))