(;AB[br]AB[cq]AB[dq]AB[eq]AB[ep]AB[er]AB[fr]AB[fs]AW[aq]AW[bq]AW[bp]AW[cp]AW[dp]AW[eo]AW[fo]AW[fp]AW[fq]AW[gr]AW[gs]AW[hq]C[White to kill.]AP[goproblems]
(;W[ds];B[cs]
(;W[ar];B[dr]
(;W[as]TR[bs]C[Black cannot play at B1 so she is dead.RIGHT])
(;W[bs];B[as]C[Black can survive winning the ko.]))
(;W[dr];B[ar]C[Black is alive!])
(;W[bs];B[as];W[ar];B[dr]C[Black can survive winning the ko.]))
(;W[cs];B[ds]
(;W[ar];B[cr]C[Black is alive!])
(;W[cr];B[bs]C[Black is alive!]))
(;W[cr];B[cs]C[Black is alive!])
(;W[bs];B[cr]
(;W[ar];B[ds]C[Black is alive!])
(;W[ds];B[ar]
(;W[dr];B[cs]C[Black is alive!])
(;W[cs]C[Black is alive in seki.])))
(;W[ar];B[ds]
(;W[cr];B[bs]
(;W[as];B[cs]C[Black is alive!])
(;W[cs];B[dr]C[Black is alive!]))
(;W[bs];B[cr]C[Black is alive!])
(;W[as];B[cs]C[Black is alive!])
(;W[cs];B[bs]C[Black is alive!])))