(;AB[rb]AB[rd]AW[rc]AB[qc]AB[oc]AB[pc]AB[nb]AB[mc]AB[lc]AW[nc]AW[nd]AW[od]AW[pd]AW[qd]AW[ob]AB[la]AB[re]AW[qe]AW[rf]AW[qg]C[White to do something good.]AP[goproblems]
(;W[sc]
(;B[sb]
(;W[qb];B[sd]
(;W[rc];B[sc]
(;W[pb];B[rc]C[The two stone edge squeeze to reduce black's liberties. Both groups have three liberties now and it's white's turn, but white needs an approach move. How to handle this?]
(;W[na];B[mb]
(;W[ra]TR[na]TR[ra]C[]
(;B[oa]
(;W[sf];B[ma]
(;W[se];B[qa];W[sa]C[RIGHT])
(;W[qa];B[na];W[se];B[pa];W[sa]C[RIGHT]))
(;W[qa];B[ma];W[sf];B[na];W[se];B[pa];W[sa]C[RIGHT])
(;W[pa];B[ma];W[sf];B[oa]C[ko]))
(;B[pa]
(;W[qa]C[RIGHT])
(;W[oa];B[ma];W[qa]C[RIGHT])
(;W[sf];B[qa];W[oa];B[qa]
(;W[se]C[RIGHT])
(;W[pa];B[ma]
(;W[se];B[qa])
(;W[qa];B[sa])
(;W[sa];B[qa]))))
(;B[qa]C[Because of the two marked hanes black needs another three moves to capture white, so white wins the race :)CHOICE]TR[na]TR[ra]
(;W[sf];B[pa];W[oa];B[qa]
(;W[se]C[RIGHT])
(;W[pa];B[ma]
(;W[se];B[qa])
(;W[qa];B[sa])
(;W[sa];B[qa])))
(;W[oa];B[ma])
(;W[pa];B[ma];W[sf];B[oa]C[ko]))
(;B[sf];W[sg];B[qa];W[se]C[Black gets an indirect ko.RIGHT]))
(;W[qa];B[ra]
(;W[sf];B[oa])
(;W[oa];B[ma]))
(;W[oa];B[qa])
(;W[pa];B[ra])
(;W[sf];B[ra]
(;W[se];B[qa])
(;W[qa];B[oa])
(;W[oa];B[qa])))
(;W[ra];B[oa];W[qa];B[na]
(;W[sf];B[pa])
(;W[mb];B[ma];W[sf];B[pa]))
(;W[qa];B[ra];W[sf];B[oa])
(;W[pa];B[na])
(;W[oa];B[na];W[ra];B[qa])
(;W[sf];B[oa]
(;W[pa];B[qa])
(;W[qa];B[ra])
(;W[ra];B[pa])
(;W[mb];B[na];W[ma];B[lb]))
(;W[mb];B[na]
(;W[ma];B[lb])
(;W[oa];B[ma]
(;W[qa];B[ra])
(;W[ra];B[qa]))
(;W[ra];B[oa];W[qa];B[ma];W[sf];B[pa])))
(;W[na]C[];B[pb]C[Black lives. You could have killed after he played T18.]))
(;W[na]C[];B[pb]C[Black lives. You could have killed after he played T18.]))
(;W[pb];B[qb])
(;W[se];B[sd];W[rc];B[sc];W[qb];B[pb])
(;W[na]C[];B[pb]C[Black lives. You could have killed after he played T18.]))
(;B[qb]
(;W[se]C[T18 is a bit better.RIGHT])
(;W[sb]C[Best sequence for bothRIGHT])))
(;W[na]C[NOTTHIS])
(;W[qb];B[sc];W[pb];B[rc]C[White cannot win this.])
(;W[mb];B[na]))
maba