(;AB[ac]AB[bc]AB[cc]AB[dc]AB[eb]AW[ec]AW[fb]AW[ed]AW[dd]AW[cd]AW[ad]AW[bd]AB[ca]C[White to kill.]AP[goproblems]
(;W[db];B[ea]
(;W[fa];B[da];W[ba];B[cb];W[ab]C[Gote seki. White can do better.])
(;W[da];B[cb]))
(;W[ea];B[bb]
(;W[aa];B[db]C[Black is alive.])
(;W[db];B[aa];W[cb]C[Nice.RIGHT]))
(;W[bb];B[ea]
(;W[cb];B[db];W[ba];B[ab]C[Ko. White can do better.])
(;W[db];B[cb]))
(;W[cb];B[ea]
(;W[ba];B[bb];W[da];B[db])
(;W[bb];B[db];W[ba];B[ab]C[Ko. White can do better.]))
(;W[da];B[ea];W[cb];B[db]))