(;AB[ac]AB[bb]AB[bd]AB[cc]AB[da]AB[ea]AB[db]AW[fa]AW[fb]AW[eb]AW[dc]AW[cd]AW[be]AW[dd]AW[ba]AW[cf]AP[goproblems]
(;B[cb];W[ae]
(;B[aa];W[ab]C[white takes the ko first])
(;B[ad];W[ab];B[aa]C[black takes the ko firstRIGHT]))
(;B[aa];W[ab]C[white takes the ko first]))