(;AB[sc]AB[sd]AB[rc]AB[qc]AB[qd]AB[pd]AB[pe]AB[pf]AB[pg]AB[og]AB[oh]AW[oi]AW[pi]AW[ph]AW[qi]AW[qh]AW[qg]AW[qf]AW[qe]AW[re]AW[rd]AW[se]AB[ni]AB[mj]AB[nj]AB[oj]AW[sf]AB[rg]AB[rh]AB[ri]AW[qj]AW[rj]AW[rk]AW[sk]AB[pj]AB[pk]AB[qk]AB[rl]AB[sl]C[Black to do his best. First move matters!]AP[goproblems]
(;B[sj]
(;W[si]
(;B[sh]C[Ko, good job!CHOICERIGHT])
(;B[sg]C[Seki, not quite!]))
(;W[sg];B[sh];W[si]C[Ko, good job! -Suggested by BartTM.CHOICERIGHT])
(;W[ne]C[Play at the marked point.]TR[sh];B[sh];W[nf]TR[rf]C[And again.];B[rf];W[si]C[Thousand year ko, black can come back later and white can't do anything about this.-Suggested by BartTM, thanks!CHOICERIGHT]))
(;B[si];W[sg]C[Seki.])
(;B[sh];W[sj]C[Seki.])
(;B[sg];W[si]C[Seki.])
(;B[rf];W[si]C[White is alive with points, yikes!]))