(;AW[ae]AW[be]AW[ce]AW[de]AW[ed]AW[ec]AW[eb]AW[fa]AW[fb]AW[ff]AW[gc]AB[bd]AB[cd]AB[dd]AB[dc]AB[cb]AB[da]C[White to kill.]AP[goproblems]
(;W[ad];B[bc])
(;W[ac];B[ad])
(;W[db];B[bc])
(;W[bb];B[bc])
(;W[ab];B[bc])
(;W[ba];B[bc])
(;W[bc];B[ad]
(;W[bb];B[ba]
(;W[db];B[ab])
(;W[ab];B[db]C[This will turn into ko or seki.]))
(;W[ba];B[bb])
(;W[db]
(;B[bb]C[CHOICE]
(;W[ac];B[cc];W[ca]C[RIGHT])
(;W[ca];B[ac];W[ea];B[aa])
(;W[ab];B[cc];W[ba];B[ac];W[ea];B[aa]C[White gets a ko ... but you could have killed.]))
(;B[ab]C[CHOICE]
(;W[cc];B[ac])
(;W[bb];B[ba])
(;W[ba]C[RIGHT])))))