(;AW[sb]AW[rb]AB[sc]AB[rc]AB[rd]AB[qd]AB[od]AB[oe]AB[of]AB[pf]AW[qc]AB[pd]AW[pc]AW[oc]AW[nc]AW[nd]AW[ne]AW[nf]AW[ng]AW[og]AW[pg]AW[qg]AW[rg]C[2. Black lives]AP[goproblems] (;B[se]C[If Black wants to live unconditionally, his only choice is the diagonal move at 1. That gives him two sure eyes. RIGHT]) (;B[rf] (;W[qf];B[qe];W[sf];B[se]LB[rf:1]LB[qf:2]LB[qe:3]LB[sf:4]LB[se:5]LB[re:a]C[Attaching with Black 1 gives a ko. If White plays 2 at 3, then Black 2, White 5, Black 4, White 'a' gives a seki.]) (;W[qe];B[qf];W[se];B[sf];W[re]C[sekiCHOICE])))