Problem 13616 but with a twist. Either kill all the stones or prove that it can not be done.
Thanks to Tails and Sandal.
(;AB[ma]AB[mb]AB[mc]AB[md]AB[me]AB[ne]AB[of]AB[pf]AB[qf]AB[qe]AB[re]AB[ob]AW[rb]AW[rd]AW[qd]AW[pe]AW[oe]AW[od]AW[nd]AW[nc]AW[nb]AW[oa]AW[pa]SZ[19]AB[na]C[Can Black kill the whole group? If you think so, go ahead. If you think White can live with at least part of the group click at O14 (Alive)]LB[nf:Alive]CA[windows-874]AP[MultiGo:4.4.4]MULTIGOGM[1]
(;B[qb];W[qc]
(;B[qa];W[ra]
(;B[pb];W[sd]C[White lives.])
(;B[oc];W[pb]C[White cannot save all, but lives anyway.])
(;B[pc];W[pb])
(;B[sd];W[pb])
(;B[pd];W[pc];B[pb];W[oa];B[pa];W[oc]))
(;B[pb];W[ra]
(;B[qa];W[sd]C[White lives.])
(;B[sd];W[qa]
(;B[pc];W[sc])
(;B[oc];W[pc])
(;B[sc];W[sb])
(;B[sb];W[pc]))
(;B[pc];W[qa])
(;B[oc];W[pd]
(;B[qa];W[sd])
(;B[sd];W[qa])
(;B[sc];W[qa]))
(;B[sc];W[qa]
(;B[sd];W[sb])
(;B[rc];W[sd])
(;B[sb];W[sd])
(;B[pc];W[sd])
(;B[oc];W[pc])))
(;B[pc];W[pd]
(;B[qa];W[ra]
(;B[pb];W[sd])
(;B[sd];W[pb]))
(;B[pb];W[ra]
(;B[qa];W[sd])
(;B[sd];W[qa]
(;B[sb];W[oc]
(;B[pb];W[sc];B[rc];W[sa])
(;B[sc];W[pb]))
(;B[sc];W[sb]))
(;B[sc];W[qa])
(;B[sb];W[qa];B[sd];W[oc]
(;B[pb];W[sc];B[rc];W[sa])
(;B[sc];W[pb])))
(;B[sd];W[qa])
(;B[ra];W[oc]))
(;B[sd];W[pb])
(;B[oc];W[pd]
(;B[qa];W[ra]
(;B[pb];W[sd])
(;B[sd];W[pb]))
(;B[pb];W[ra]
(;B[qa];W[sd])
(;B[sd];W[qa])
(;B[sc];W[qa]))
(;B[sd];W[pb]))
(;B[sc];W[pb]))
(;B[pb];W[qa]C[White lives.])
(;B[pc];W[qb]C[]
(;B[pd]C[];W[qc]C[Nice capture, but White lives.])
(;B[qc];W[pd]
(;B[rc];W[sc])
(;B[pb];W[qa])
(;B[sd];W[rc]))
(;B[qa];W[pb]
(;B[pd];W[qc]C[White lives with the main part.])
(;B[qc];W[rc]))
(;B[pb];W[qa]
(;B[pd];W[qc]
(;B[oc];W[sd]C[White lives with the main part.])
(;B[sc];W[oc])
(;B[sd];W[oc]))
(;B[qc];W[rc])
(;B[sd];W[sc];B[pd];W[qc]C[White lives in sente.])))
(;B[qa];W[pb]
(;B[pc]C[];W[qb]
(;B[pd];W[qc]C[White lives with the main part.])
(;B[qc];W[rc]))
(;B[qb];W[pc])
(;B[qc];W[pc]))
(;B[oc];W[pd]
(;B[qb];W[pb])
(;B[pb];W[qa])
(;B[qa];W[pb]))
(;B[sd];W[pb])
(;B[nf]AW[ma]AW[mb]AW[mc]AW[md]AW[me]AW[ne]AW[of]AW[pf]AW[qf]AW[qe]AW[re]AW[ob]AB[rb]AB[rd]AB[qd]AB[pe]AB[oe]AB[od]AB[nd]AB[nc]AB[nb]AB[oa]AB[pa]AW[na];W[qb]C[You think the corner can live, right? The colors have been swapped so that you can prove it. Save as much as you can; losing a few stones extra but keeping sente is acceptable too.]
(;B[qc];W[pb]
(;B[ra];W[qa]
(;B[sd]C[Easy!RIGHT])
(;B[sc]C[Right!RIGHT])
(;B[oa];W[oc]
(;B[pd];W[sd]C[One eye only.])
(;B[sd];W[pd]C[A bit careless to let that may stones fall away, but you're alive in sente.RIGHT])
(;B[sc];W[pd]C[You reached the objective in sente, even though your opponent gets more than he should.RIGHT])
(;B[pc];W[pd]
(;B[sd]C[Alive, but in gote AND losing most of your stones - that is not good enough.])
(;B[sc]C[Alive in gote with just a small part of your group - you could have saved a lot more than this.]))
(;B[sb];W[sd]
(;B[pc];W[pd])
(;B[sc];W[se];B[pc];W[pd])))
(;B[pc];W[oc]
(;B[pd];W[sd])
(;B[sd];W[pd]C[Alive in sente. A big loss in stones but okay.RIGHT])
(;B[sc];W[pd]C[There's a price to pay for getting sente. Well I'll let it pass.RIGHT])
(;B[sb];W[sd])
(;B[oa];W[pd]
(;B[sd]C[Alive, but in gote AND losing most of your stones - that is not good enough.])
(;B[sc]C[Alive in gote with just a small part of your group - you could have saved a lot more than this.])))
(;B[oc];W[pc]
(;B[pd];W[sd]
(;B[rc];W[oa])
(;B[sc];W[rc])
(;B[oa];W[rc]))
(;B[sd];W[pd]C[Alive in sente albeit with just a small part of your group.RIGHT])
(;B[sc];W[pd]C[Alive in sente albeit with just a small part of your group.RIGHT])
(;B[sb];W[sd])
(;B[oa];W[sd]))
(;B[pd];W[sd]))
(;B[qa];W[ra])
(;B[pc];W[ra]
(;B[sc];W[sb]C[Ko])
(;B[oc];W[qa]
(;B[sc];W[sb]C[Ko])
(;B[sb];W[sd])
(;B[sd];W[sb];B[sc];W[rc]C[Ko])
(;B[oa];W[sc]
(;B[sd];W[sb])
(;B[sb];W[sd]))))
(;B[sc];W[ra];B[pc];W[sb]C[Ko])
(;B[sd];W[ra]
(;B[pc];W[sb])
(;B[sb];W[oc])))
(;B[pb];W[pc]
(;B[oc];W[qa]
(;B[qc];W[ob]
(;B[ra];W[sd]MA[pd]MA[rc])
(;B[pd];W[sd]
(;B[pb];W[oa]MA[rc]C[S17 is just a false eye. Black is dead.])
(;B[ra];W[rc])
(;B[oa];W[rc])
(;B[sc];W[rc]))
(;B[sc];W[ra]))
(;B[ob];W[pd])
(;B[pd];W[ob]
(;B[qc];W[sd]
(;B[pb];W[oa]MA[rc]C[S17 is just a false eye. Black is dead.])
(;B[ra];W[rc])
(;B[oa];W[rc])
(;B[sc];W[rc]))
(;B[ra];W[qc]
(;B[rc];W[pa];B[sd];W[sb])
(;B[pa];W[rc]))
(;B[sc];W[ra]))
(;B[ra];W[qc]
(;B[rc];W[ob])
(;B[sd];W[rc])
(;B[pd];W[ob])
(;B[ob];W[pd])))
(;B[pd];W[qa])
(;B[qc];W[qa]))
(;B[pc]
(;W[pb]
(;B[qc];W[ra]
(;B[sc];W[sb]C[Ko])
(;B[oc];W[qa]
(;B[sc];W[sb]C[Ko])
(;B[sb];W[sd])
(;B[sd];W[sb];B[sc];W[rc]C[Ko])
(;B[oa];W[sc]
(;B[sd];W[sb])
(;B[sb];W[sd]))))
(;B[ra];W[oc]
(;B[pd];W[qa];B[sd];W[se])
(;B[qa];W[pd]
(;B[sd];W[se]
(;B[qc];W[sc];B[rc];W[sb])
(;B[rc];W[sb])
(;B[sb];W[rc]
(;B[sc];W[qc])
(;B[qc];W[sc]))
(;B[sc];W[qc]))
(;B[qc];W[sd])
(;B[sc];W[qc])
(;B[sb];W[sd]))
(;B[qc];W[pd]
(;B[sd]C[A small life in gote ain't good enough.])
(;B[sc]C[Alive but too small, and losing sente.]))
(;B[sd];W[pd];B[qc]C[Alive in gote.])
(;B[sc];W[qc])))
(;W[qc];B[pb]))
(;B[qa];W[ra]
(;B[pb];W[pc])
(;B[sa];W[pb]
(;B[pc];W[ra])
(;B[ra];W[rc])))
(;B[ra];W[qc]
(;B[pc];W[rc]
(;B[sc];W[sb]
(;B[sa];W[pb])
(;B[qa];W[sd])
(;B[pb];W[sd])
(;B[pd];W[sd])
(;B[oc];W[sd])
(;B[sd];W[pb]))
(;B[pb];W[sd]
(;B[qa];W[pd]
(;B[sb];W[oc])
(;B[oc];W[sb])
(;B[qd];W[sb]))
(;B[pd];W[sb])
(;B[sb];W[pd]
(;B[qa];W[oc])
(;B[qd];W[qa])
(;B[oc];W[qa]))
(;B[sc];W[pd]))
(;B[qa];W[sd]
(;B[sb];W[pb])
(;B[pb];W[pd]
(;B[sb];W[oc])
(;B[oc];W[sb])
(;B[qd];W[sb]))
(;B[pd];W[pb])
(;B[oc];W[pd]
(;B[pb];W[sb])
(;B[sb];W[pb]))
(;B[sc];W[pd]))
(;B[pd];W[pb])
(;B[sd];W[pb]))
(;B[pb];W[pc]
(;B[qa];W[pd])
(;B[oc];W[qa]
(;B[rc];W[ob])
(;B[sd];W[rc])
(;B[pd];W[ob]
(;B[rc];W[pa];B[sd];W[sb])
(;B[pa];W[rc]))
(;B[ob];W[pd]))
(;B[pd];W[qa])
(;B[rc];W[qa]))
(;B[oc];W[pb]
(;B[qa];W[pd])
(;B[pd];W[qa])
(;B[pc];W[pd])
(;B[rc];W[qa]))
(;B[rc];W[qa])
(;B[sd];W[rc]
(;B[qa];W[pb]
(;B[sc];W[sb])
(;B[sb];W[sc])
(;B[pc];W[sb]))
(;B[sc];W[pb]
(;B[qa];W[sb])
(;B[sb];W[qa])
(;B[pc];W[qa]))
(;B[pb];W[pc]
(;B[oc];W[pd])
(;B[pd];W[qa])
(;B[qa];W[pd])
(;B[sc];W[qa])
(;B[sb];W[qa]))
(;B[pc];W[pb]))
(;B[qa];W[rc]
(;B[sc];W[sb]
(;B[sa];W[pb])
(;B[pb];W[sd])
(;B[sd];W[pb])
(;B[pc];W[sd])
(;B[oc];W[sd])
(;B[pd];W[sd]))
(;B[pc];W[sd]
(;B[sb];W[pb])
(;B[pb])
(;B[pd];W[pb])
(;B[oc];W[pd]
(;B[pb])
(;B[sb];W[pb]))
(;B[sc];W[pd]))
(;B[pb];W[sd]
(;B[pd];W[pc])
(;B[pc];W[pd]
(;B[sb];W[oc])
(;B[oc];W[sb])
(;B[qd];W[sb]))
(;B[sb];W[pd]))
(;B[sb];W[pc]
(;B[sc];W[pd])
(;B[pd];W[sd]))
(;B[oc];W[pc]
(;B[pb];W[sd])
(;B[pd];W[sd]))
(;B[sd];W[pb]
(;B[sc];W[sb])
(;B[sb];W[sc])
(;B[pc];W[sb]))
(;B[pd];W[pb];B[sc];W[sb]))))
(;B[qc];W[pc]
(;B[pb];W[qa]
(;B[qb];W[ra])
(;B[rc];W[qb])
(;B[sd];W[qb]))
(;B[qb];W[pb])
(;B[qa];W[pb])
(;B[rc];W[qb])
(;B[sd];W[qb])))