(;AW[ad]AW[be]AW[ce]AW[cd]AW[cc]AW[cb]AW[db]AW[da]AB[ea]AB[eb]AB[ec]AB[dc]AB[de]AB[df]AB[cf]AB[bf]AB[af]AB[ae]AB[ee]AB[ed]C[Best for B?]AP[goproblems]
(;B[bb];W[bc]
(;B[aa];W[ac])
(;B[ab];W[ac]
(;B[ba];W[ca])
(;B[dd];W[ba]))
(;B[ba];W[ab]))
(;B[ab];W[ac]
(;B[ba];W[bb])
(;B[bb];W[bc];B[ba];W[ca])
(;B[bc];W[bd]
(;B[bb];W[ba])
(;B[ba];W[bb])))
(;B[bc];W[bb]
(;B[ab];W[bd];B[ba];W[ac])
(;B[ac];W[ab];B[bd];W[ad])
(;B[bd];W[ac])
(;B[ba];W[ab]))
(;B[ac]
(;W[bd]
(;B[bb];W[ba]
(;B[aa];W[bc]
(;B[dd];W[ab])
(;B[ca];W[ab]C[W lives in eternal ko.])
(;B[ab]))
(;B[ab];W[bc])
(;B[bc];W[ab])
(;B[dd]
(;W[ab]C[CHOICE];B[aa]C[W could choose ko or seki.RIGHT])
(;W[aa]C[W could choose ko or sekiCHOICERIGHT])))
(;B[ab];W[ba]
(;B[bb];W[bc])
(;B[dd];W[bb])
(;B[bc];W[bb]))
(;B[bc];W[bb])
(;B[aa];W[bb]
(;B[ba];W[ab])
(;B[ab];W[ba]))
(;B[ba];W[bb]C[CHOICE]
(;B[ab]C[Seki
note w A loses the whole group.RIGHT]LB[bc:A])
(;B[dd];W[ab]))
(;B[dd];W[bb]
(;B[ba];W[ab])
(;B[ab];W[ba])))
(;W[ab]C[This is what W should do.]
(;B[bc];W[bb];B[bd];W[ad])
(;B[bd];W[bc];B[ad];W[ba]C[RIGHT])))
(;B[ba];W[bc]
(;B[ab];W[ac];B[bb];W[ca])
(;B[bb];W[ab]))
(;B[aa];W[bc])
(;B[bd];W[bc];B[ab];W[bb];B[ba]))