Problem 15853 goproblems.com


Author	MrMoto	Created	2012-02-13
Difficulty	7 dan (history)	Source	N/A
AVG solve time	82 sec	Stars	3 (2 votes)
User attempts	55 / 247	Collections	Corner based, Self made
Genre	life and death	Your attempts	N/A
Similar problems
Created	2012-02-13
Source	N/A
Stars	3 (2 votes)
Collections	Corner based, Self made
Your attempts	N/A

(;AW[qb]AW[oc]AW[pd]AW[qd]AW[rd]AB[oa]AB[ma]AB[mb]AB[nb]AW[ob]AB[nc]AB[nd]AB[od]AB[oe]AB[pe]AB[qe]AB[re]AB[se]AB[me]C[This should be an easy kill for Black, right?]AB[nf]AP[goproblems] (;B[rb];W[pc] (;B[pa]C[Well done! This is the simplest way. White cannot prevent the connection to S18. :)RIGHT]) (;B[qa];W[ra]C[This is going to lead to ko. But tell you what: I'll count it as a success if you can make the ko fight as hard as possible for White. Keep going!] (;B[sa];W[pa] (;B[pb];W[ka]LB[ja:A]C[Please respond to White's ko threat at A.FORCE];B[ja];W[pa] (;B[rc];W[sd] (;B[pb];W[kb]LB[jb:A]C[FORCE];B[jb];W[pa] (;B[ra];W[sc];B[pb]C[Well done! But next time, try to kill without ko. ;)RIGHT]) (;B[na];W[ra]C[Now Black needs 2 threats.]) (;B[sc];W[ra]C[Now Black needs 2 threats.]) (;B[sb];W[ra]C[White lives in double ko.])) (;B[sc];W[ra]C[Now Black needs 2 threats.]) (;B[na];W[ra]C[Now Black needs 2 threats.]) (;B[sb];W[ra]C[White lives in double ko.])) (;B[na];W[rc] (;B[pb];W[sb] (;B[pa];W[ra]) (;B[ra];W[pa]) (;B[qc];W[ra]C[Unwise -- now you need another ko threat to get back to where you just were.]) (;B[sc];W[pa] (;B[ra];W[sb]) (;B[sb];W[sd]) (;B[sd];W[ra]C[Black needs 1 threat.]))) (;B[sc];W[ra]C[Black needs1 threat.]) (;B[sd];W[ra]C[Now Black needs 2 threats.])) (;B[sd];W[rc] (;B[sc];W[ra]C[White lives in double ko.]) (;B[pb]C[White only needs 1 more threat.])) (;B[sc];W[na] (;B[sd];W[rc]C[White lives in double ko.]) (;B[rc];W[sd] (;B[ra];W[qc]) (;B[oa];W[ra]) (;B[qc];W[ra]C[Black needs 1 threat.])))) (;B[rc];W[sd] (;B[pb]C[White only needs 2 threats.]) (;B[sc];W[ra]C[Now Black needs 2 threats.]) (;B[qc];W[ra]C[Black needs 1 threat.])) (;B[sc];W[na] (;B[sd];W[rc]C[White lives in double ko.]) (;B[rc];W[sd] (;B[oa];W[ra]) (;B[qc];W[ra]C[Black needs 1 threat.]) (;B[ra];W[qc]))) (;B[sd];W[rc] (;B[pb]C[White only needs 1 threat.]) (;B[sc];W[na]C[White lives in double ko.])) (;B[na];W[rc] (;B[pb];W[sb] (;B[sc];W[pa] (;B[sd];W[ra]C[Black needs 1 threat.]) (;B[sb];W[sd]) (;B[ra];W[sb])) (;B[qc];W[ra]C[A mistake -- now Black needs another threat just to return to the previous position.])) (;B[sc];W[ra]C[Black needs 1 threat.]) (;B[sd];W[ra]C[Now Black needs 2 threats.]))) (;B[pa];W[sb] (;B[sa]C[White only needs 2 threats.]) (;B[rc];W[sc];B[sa]C[White only needs 1 threat.])) (;B[sb];W[pa]) (;B[rc];W[sd] (;B[pa];W[sb];B[sa]C[White only needs 2 threats.]) (;B[sa];W[pa] (;B[pb]C[White only needs 2 threats.]) (;B[sc];W[ra]C[Now Black needs 2 threats.]) (;B[qc];W[ra]C[Black needs 1 threat.]))) (;B[sc];W[pa]) (;B[sd];W[rc] (;B[sa];W[pa];B[pb]C[White only needs 1 threat.]) (;B[pa];W[sb]) (;B[sc];W[sb]))) (;B[ra];W[rc];B[qa];W[pa];B[pb]C[White only needs 1 threat. You could have killed unconditionally, or at least found a more favourable ko.]) (;B[sb];W[rc]) (;B[rc];W[sd] (;B[pa]C[Well done! S17 was unnecessary, though. (You could have just played Q19.)RIGHT]) (;B[qa];W[ra] (;B[pa];W[sb];B[sa]C[White only needs 2 threats.]) (;B[sa];W[pa])) (;B[ra];W[pa] (;B[na];W[sc] (;B[sb];W[qc]) (;B[qc];W[sb]) (;B[qa];W[sb];B[pb]C[White only needs 1 threat.])) (;B[qc];W[sc] (;B[na];W[sb]) (;B[sb];W[na]C[Now Black needs 1 threat.]) (;B[qa];W[na];B[pb]C[Black kills with double ko! That's always fun.RIGHT])) (;B[sc];W[qc] (;B[na];W[sb]) (;B[qa];W[na]C[Black needs 1 threat.])) (;B[sb];W[qa] (;B[na];W[qc]) (;B[qc];W[na]C[Black needs 1 threat.])) (;B[qa];W[qc]C[This is going to lead to ko. But tell you what: I'll count it as a success if you can make the ko fight as hard as possible for White. Keep going!] (;B[sc];W[na]C[Black needs 1 threat.]) (;B[na];W[sc]C[Now White only needs 2 threats.]) (;B[pb];W[ka]LB[ja:A]C[Please respond to White's threat at A.FORCE];B[ja];W[pa] (;B[sc];W[na]C[Black needs 1 threat.]) (;B[na];W[sc];B[pb];W[kb]LB[jb:A]C[FORCE];B[jb];W[pa]LB[jc:T]C[Play T to tenuki.FORCE];B[jc];W[sb];B[pb]C[Well done! White needs 1 more threat. But next time try to avoid ko. ;)RIGHT])))) (;B[sc];W[pa] (;B[na];W[ra]) (;B[ra];W[qc] (;B[na];W[sb]) (;B[qa];W[na]C[Black needs 1 threat.])) (;B[qc];W[na];B[ra];W[qa];B[oa]C[White only needs 1 threat.])) (;B[sb];W[pa] (;B[na];W[ra]) (;B[ra];W[qa] (;B[na];W[qc]) (;B[qc];W[na]C[Black needs 1 threat.])) (;B[qc];W[ra])) (;B[sa];W[pa] (;B[na];W[qa]) (;B[qa];W[ra]C[Now Black needs 3 ko threats. :O]) (;B[sc];W[qc] (;B[ra]C[Gote seki.]) (;B[qa];W[na]C[White lives in double ko.]) (;B[na];W[qa])) (;B[qc];W[sc] (;B[na];W[qa]) (;B[qa];W[ra]C[Black needs 1 threat.]) (;B[ra]C[Gote seki.])) (;B[ra];W[sc])) (;B[qc];W[ra])) (;B[sa];W[pa] (;B[qa];W[ra]C[Now Black needs 2 threats.]) (;B[ra];W[rc]) (;B[na];W[rc]) (;B[sb];W[rc]) (;B[rc];W[sd] (;B[na];W[qa]) (;B[qa];W[ra]C[Now Black needs 3 ko threats. :O]) (;B[sc];W[qc] (;B[ra]C[Gote seki.]) (;B[qa];W[na]C[White lives in double ko.]) (;B[na];W[qa])) (;B[qc];W[sc] (;B[na];W[qa]) (;B[qa];W[ra]C[Black needs 1 threat.]) (;B[ra]C[Gote seki.])) (;B[ra];W[sc])) (;B[sc];W[rc] (;B[sd];W[qa]) (;B[na];W[qa]) (;B[qa];W[ra]C[White lives in double ko.]) (;B[ra];W[sd])) (;B[sd];W[rc] (;B[sc];W[qa]) (;B[qa];W[ra]C[White lives in double ko.]))) (;B[sc];W[pa] (;B[na];W[rc]) (;B[ra];W[rc] (;B[sd];W[qa]) (;B[na];W[qa]) (;B[qa];W[na]C[Black needs 1 threat.])) (;B[sd];W[rc]) (;B[rc];W[sd] (;B[na];W[ra]) (;B[ra];W[qc]) (;B[qc];W[na];B[ra];W[qa];B[oa]C[White only needs 1 threat.]))) (;B[sd];W[rc] (;B[sc];W[pa]) (;B[pa];W[ra]) (;B[sb];W[pa]) (;B[ra];W[qa]) (;B[qa];W[pa] (;B[pb];W[sb] (;B[sc];W[ra]) (;B[qc]C[White only needs 1 threat.]) (;B[ra];W[pa]C[Black needs 1 threat.]) (;B[pa];W[ra]) (;B[na];W[ra])) (;B[na];W[ra]) (;B[sc];W[ra]) (;B[ra];W[na]C[Black needs 1 threat.]) (;B[sb];W[ra]) (;B[sa];W[ra]C[White lives in double ko.])))) (;B[pa];W[rb]) (;B[pb];W[pc]LB[ra:A]C[FORCE];B[ra];W[pa]LB[qa:A]C[FORCE];B[qa];W[na]C[Black will need 2 threats.]) (;B[qa];W[ra]LB[pc:A]C[FORCE];B[pc];W[pb]LB[rb:A]C[FORCE];B[rb];W[qc]LB[sd:A]C[FORCE];B[sd];W[sc]LB[sa:A]C[FORCE];B[sa];W[pa]LB[rc:A]C[FORCE];B[rc];W[ra]C[Black needs 1 threat.]) (;B[ra];W[qa]LB[rc:A]C[FORCE];B[rc];W[rb]LB[sd:A]C[FORCE];B[sd];W[qc]LB[sb:A]C[FORCE];B[sb];W[sc]C[Black needs 1 threat.]) (;B[sa];W[rb]C[:|]) (;B[pc];W[sb]LB[pb:A]C[FORCE];B[pb];W[ra]LB[qc:A]C[FORCE];B[qc];W[rc]LB[qa:A]C[FORCE];B[qa];W[sd]LB[rb:A]C[FORCE];B[rb]C[White only needs 1 threat.]) (;B[qc];W[rb]) (;B[rc];W[rb]LB[sd:A]C[FORCE];B[sd];W[qc]LB[sb:A]C[FORCE];B[sb];W[pa]LB[ra:A]C[FORCE];B[ra];W[sc]C[Black needs 1 threat.]) (;B[sb];W[sd]) (;B[sc];W[rb]) (;B[sd];W[rc]))