(;AB[ab]AB[bc]AB[cc]AB[ec]AB[eb]AB[ea]AW[fa]AW[fb]AW[fc]AW[gd]AW[ed]AW[dd]AW[bd]AW[ac]AW[ad]AW[cd]AP[goproblems]
(;B[cb];W[ba]
(;B[dc];W[bb];B[ca];W[aa];B[ab]C[RIGHT])
(;B[ca];W[dc];B[db]C[RIGHT]))
(;B[ba]
(;W[dc]
(;B[cb]C[This variation is given as a solution in the book, it seems to be incorrect.])
(;B[db];W[cb]C[]))
(;W[cb]C[CHOICE]))
(;B[dc];W[bb]
(;B[ba];W[aa]C[Disadv. ko])
(;B[cb];W[aa]C[]))
(;B[bb];W[ca];B[ba];W[dc];B[db]C[RIGHT]))