(;AB[qa]AB[pa]AB[pb]AB[qc]AB[qd]AB[qe]AB[qf]AW[oa]AW[ob]AW[pc]AW[pd]AW[pe]AW[pf]AB[rf]AB[se]AW[qg]AW[rg]AW[sg]AW[sf]AW[pg]AW[oc]AW[ra]TR[ra]C[To be fair: Black has one less liberty than in problem 10357, so watch your step.]AP[goproblems] (;B[qb];W[sc] (;B[sd];W[rd] (;B[rc];W[re] (;B[se];W[rb]) (;B[sd];W[rb]) (;B[rb];W[sb]) (;B[sb];W[rb]) (;B[sa];W[rb])) (;B[re];W[rb] (;B[rc];W[rd]) (;B[sb];W[rc])) (;B[rb];W[re]) (;B[sb];W[re])) (;B[rd];W[sd] (;B[sb];W[re]C[Ko]) (;B[rc];W[sb]) (;B[rb];W[sb] (;B[re];W[rc]) (;B[rc];W[re]) (;B[sa];W[re]MA[se]MA[ra]C[Dead by double ko])) (;B[re];W[rb]) (;B[sa];W[rb])) (;B[rc];W[sd] (;B[rd];W[sb]) (;B[re];W[rb]) (;B[sb];W[re]) (;B[rb];W[re])) (;B[rb] (;W[sd] (;B[rd]) (;B[rc];W[re]) (;B[sb];W[re]) (;B[re];W[sb]C[1000 year ko. If Black connects Black dies, White could make it seki. To really win the ko either side has to neglect several ko threats.]) (;B[sa];W[re])) (;W[re]C[If White can win the ko White should play this to avoid the 1000 year ko, as White needs ignore less threats to win this way.] (;B[rd];W[sd] (;B[re];W[sb]C[Ko]) (;B[rc];W[re]C[Ko]) (;B[sb];W[re]C[Ko]) (;B[sa];W[re]C[Ko])) (;B[sd];W[rd]) (;B[rc];W[sd]) (;B[sb];W[sd]) (;B[sa];W[sd]))) (;B[sb];W[sd] (;B[rd]) (;B[re];W[rb] (;B[rc];W[rd]) (;B[rd];W[rc])) (;B[rc];W[re]) (;B[rb];W[re])) (;B[re];W[rb] (;B[rc];W[sd]) (;B[sb];W[rc])) (;B[sa];W[rb] (;B[rc];W[sd] (;B[sb];W[re]) (;B[rd];W[re]) (;B[re];W[rd])) (;B[rd];W[sd]) (;B[sd];W[rd] (;B[re];W[rc]) (;B[rc];W[re])) (;B[re];W[rc]))) (;B[rb];W[qb] (;B[rd];W[sb] (;B[sc];W[rc]C[Ko, White takes first.]) (;B[rc];W[sc]) (;B[qa];W[rc])) (;B[rc];W[sb] (;B[rd];W[sc]) (;B[sc];W[rd])) (;B[sb];W[rd]) (;B[sd];W[sb]) (;B[sc];W[rd]) (;B[qa];W[pa];B[rd];W[sb];B[sc];W[rc]C[Ko]) (;B[pa];W[rc] (;B[rd];W[sc]) (;B[sb];W[rd]) (;B[sd];W[sc]) (;B[sc];W[rd]) (;B[qa];W[pb]) (;B[pb];W[qa])) (;B[sa];W[sb])) (;B[rd] (;W[qb]C[CHOICE] (;B[sc];W[rb] (;B[rc]C[A small life - safe and unconditional.RIGHT]) (;B[sb];W[rc]) (;B[sa];W[rc])) (;B[rb];W[sb] (;B[sc];W[rc]C[Ko, White takes first.]) (;B[rc];W[sc]) (;B[qa];W[rc])) (;B[rc];W[sc] (;B[rb];W[sb]) (;B[sb];W[rb])) (;B[sb];W[rb] (;B[sc];W[rc]) (;B[rc];W[sc]))) (;W[sc]C[White can also try this at her own expense...CHOICE] (;B[rb];W[sb] (;B[sd];W[qb]) (;B[qb];W[sd] (;B[re];W[rc]) (;B[rc];W[re]) (;B[sa];W[re]MA[se]MA[ra]C[Dead by double ko])) (;B[rc];W[qb]) (;B[sa]C[Ko])) (;B[qb];W[sd] (;B[sb];W[re]C[Ko]) (;B[rc];W[sb]) (;B[rb];W[sb] (;B[re];W[rc]) (;B[rc];W[re]) (;B[sa];W[re]MA[se]MA[ra]C[Dead by double ko])) (;B[re];W[rb]) (;B[sa];W[rb])) (;B[sd];W[qb] (;B[rb];W[sb]) (;B[sb];W[rb]) (;B[rc];W[rb])) (;B[rc];W[qb] (;B[rb];W[sb]) (;B[sb];W[rb])) (;B[sb] (;W[rb];B[qb];W[rc]C[Sente seki, even better. White should not play like this.RIGHT]) (;W[qb]C[CHOICE] (;B[rb]C[Unconditional and slightly bigger.RIGHT]) (;B[rc];W[rb]) (;B[sd];W[rb]))))) (;B[sc] (;W[rd]C[] (;B[qb];W[sb] (;B[sd];W[rc] (;B[re];W[rb]) (;B[rb];W[re])) (;B[re];W[rc] (;B[sd];W[rb]) (;B[rb];W[sd])) (;B[rc];W[sd]C[Sente seki. Black can capture 2 stones at S15 at the end of the game and the one White will trow in to keep it seki.RIGHT]) (;B[rb];W[sd] (;B[sa]C[Alive!RIGHT]) (;B[re]) (;B[rc];W[re]))) (;B[rb];W[qb]) (;B[rc];W[qb]) (;B[sd];W[qb]) (;B[re];W[qb]) (;B[sb];W[qb]) (;B[sa];W[qb])) (;W[qb] (;B[rd];W[rb] (;B[rc]C[RIGHT]) (;B[sb];W[rc])) (;B[rc];W[rd]) (;B[rb];W[rd]) (;B[sb];W[rd]))) (;B[rc];W[qb] (;B[rd];W[sc] (;B[rb];W[sb]) (;B[sb];W[rb])) (;B[rb];W[rd] (;B[sb];W[sd]) (;B[sd];W[sb])) (;B[sb];W[rb]) (;B[sc];W[rd])) (;B[sb];W[rb] (;B[qb] (;W[rc]) (;W[sd] (;B[sc];W[re]) (;B[rd];W[re]C[Ko]) (;B[rc];W[re]) (;B[re];W[rc]))) (;B[rc];W[qb]) (;B[rd];W[qb] (;B[sc]) (;B[rc];W[sc]))) (;B[sd];W[qb];B[rb];W[sb]) (;B[re];W[qb]) (;B[sa];W[rb] (;B[qb];W[sd] (;B[rc];W[re]) (;B[rd];W[sc]) (;B[sc];W[re]) (;B[sb];W[re])) (;B[rd];W[qb] (;B[sc];W[rc]) (;B[rc];W[sc])) (;B[sc];W[qb]) (;B[rc];W[qb]) (;B[sb];W[qb]) (;B[sd];W[qb]) (;B[re];W[qb])))