(;AB[ra]AB[rb]AB[rc]AB[qc]AB[pd]AB[od]AB[of]AB[qf]AB[nc]AB[mb]AB[mc]AB[md]AW[qb]AW[qa]AW[pc]AW[ob]AW[oc]AW[pa]AW[kb]AW[ka]AW[kc]AW[me]AW[ne]AW[nd]AW[ld]AW[ke]C[Black to do his best.]AP[goproblems](;B[ma];W[na];B[nb];W[lc];B[oa]C[A favourable Ko for black. :)RIGHT])(;B[na];W[ma](;B[nb];W[lb]C[Black is dead. If Black takes the ko White takes the outside liberty and Black still cannot approach.])(;B[la];W[nb]C[Black is dead :(]))(;B[nb];W[ma](;B[oa];W[na])(;B[na];W[lb]C[Black is dead. If Black takes the ko White takes the outside liberty and Black still cannot approach. :(]))(;B[la];W[kf]C[White plays elsewhere... Now what?](;B[nb];W[lb](;B[oa];W[na])(;B[na];W[lc])(;B[ma];W[lc]))(;B[na];W[nb]C[One eye versus a shortage of liberties.])(;B[ma];W[nb];B[na];W[lc])(;B[oa];W[na];B[nb];W[lb])))