Problem 15421 goproblems.com


Author	sestir	Created	2011-11-27
Difficulty	7 dan (history)	Source	German Championship Terwey vs Obenaus
AVG solve time	112 sec	Stars	4.5 (2 votes)
User attempts	122 / 461	Collections	Semeai / Capturing Race, Amateur Game, Corner based
Genre	endgame	Your attempts	N/A
Similar problems
Created	2011-11-27
Source	German Championship Terwey vs Obenaus
Stars	4.5 (2 votes)
Collections	Semeai / Capturing Race, Amateur Game, Corner based
Your attempts	N/A

(;AB[ps]AB[os]AB[or]AB[nr]AB[nq]AB[op]AB[oo]AB[on]AB[po]AW[qs]AW[pr]AW[pq]AW[pp]AW[qq]AW[qo]AW[pn]AW[om]AW[ol]AW[pl]AW[pk]AW[sk]AW[rk]AW[qk]C[Gain as many points as you can in this corner! (Neither side has any ko-threats.)]AW[sl]AP[goproblems] (;B[qn];W[pm] (;B[rr];W[qr] (;B[ro];W[qp] (;B[rn] (;W[sr] (;B[rp];W[rq] (;B[rs];W[sp] (;B[so];W[rm] (;B[sq];W[ss] (;B[rr];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rs])) (;B[oq];W[qm] (;B[rr];W[sp]C[oops ... wrong order]) (;B[sp];W[sn]C[oops ... wrong order]) (;B[rs];W[sp]C[oops ... wrong order])) (;B[rs];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rr];B[oq];W[sp])) (;B[sp];W[qm])) (;B[oq];W[ss] (;B[rr];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[sq];W[qm] (;B[rr];W[sp]C[oops ... wrong order]) (;B[sp];W[sn]C[oops ... wrong order]) (;B[rs];W[sp]C[oops ... wrong order])))) (;B[oq];W[ss] (;B[so];W[rm] (;B[rr]C[];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs]C[];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[sq];W[qm])) (;B[rr];W[rm];B[so];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs];W[rm];B[so];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]))) (;B[sq];W[rs]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[ss];W[rs])) (;B[rs] (;W[rp] (;B[sp] (;W[so] (;B[oq];W[sq];B[sn]C[You win! However P3 would have been better immediately at T6, to avoid ko.RIGHT]) (;B[sq];W[rq];B[sp];W[rm]) (;B[rq];W[sq];B[oq];W[ss];B[rr];W[rm]) (;B[sn];W[rq] (;B[so];W[rm];B[sq];W[ss] (;B[rr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;B[oq];W[ss] (;B[so];W[rm];B[sq];W[qm]) (;B[rr];W[rm];B[so];W[qm]) (;B[rs];W[rm];B[so];W[qm])))) (;W[rq];B[so]C[Very well done!RIGHT])) (;B[oq];W[rq] (;B[so];W[ss]) (;B[sp];W[ss];B[so];W[rm]))) (;W[sp] (;B[rq]C[Very well done!RIGHT]) (;B[rp];W[rq] (;B[so];W[rm] (;B[sq];W[ss] (;B[rr];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rs])) (;B[oq];W[qm] (;B[rr];W[sp]C[oops ... wrong order]) (;B[sp];W[sn]C[oops ... wrong order]) (;B[rs];W[sp]C[oops ... wrong order])) (;B[rs];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rr];B[oq];W[sp])) (;B[sp];W[qm])) (;B[oq];W[ss] (;B[rr];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[sq];W[qm]))) (;B[oq];W[ss] (;B[so];W[rm] (;B[rr]C[]) (;B[rs]C[]) (;B[sq])) (;B[rr];W[rm];B[so]) (;B[rs];W[rm];B[so]))))) (;B[sq];W[rs] (;B[ss];W[rq] (;B[sp];W[sr]) (;B[sr];W[sp];B[sr];W[rp])) (;B[rq];W[rp];B[ss];W[sp])) (;B[rq];W[rp] (;B[rs];W[sq];B[so];W[rm];B[sp];W[ss];B[rr];W[qm]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[sq];W[rs];B[ss];W[sp])) (;B[sp];W[rs] (;B[sq];W[rq]) (;B[rq];W[rp])) (;B[ss];W[rs]) (;B[so];W[rs];B[rq];W[rp]) (;B[oq];W[rs] (;B[rq];W[rp]) (;B[sq];W[rq]))) (;W[rp];B[sp] (;W[rs] (;B[sr]C[RIGHT]) (;B[sq];W[sr];B[ss];W[so];B[oq];W[sr])) (;W[sq];B[so];W[rq] (;B[oq]C[Very well done!RIGHT]) (;B[sr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;W[sr];B[rs] (;W[so] (;B[oq];W[sq];B[sn]C[You win! However P3 would have been better immediately at T6, to avoid ko.RIGHT]) (;B[sq];W[rq];B[sp];W[rm]) (;B[rq];W[sq];B[oq];W[ss];B[rr];W[rm]) (;B[sn];W[rq] (;B[so];W[rm];B[sq];W[ss] (;B[rr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;B[oq];W[ss] (;B[so];W[rm];B[sq];W[qm]) (;B[rr];W[rm];B[so];W[qm]) (;B[rs];W[rm];B[so];W[qm])))) (;W[rq];B[so]C[Very well done!RIGHT])))) (;B[sn];W[rm];B[rn];W[sp] (;B[rp];W[rq];B[so];W[sq]) (;B[sq];W[rp];B[rs];W[qm])) (;B[rp];W[rn];B[rq];W[rs]) (;B[rm];W[rp];B[sp];W[sq] (;B[so];W[rn];B[sn];W[sm]) (;B[sn];W[qm];B[rn];W[rl]) (;B[rn];W[so];B[sn];W[rl]))) (;B[rn];W[ro];B[rp];W[qp] (;B[so];W[rq] (;B[sp];W[sq];B[sn];W[rm]) (;B[sq];W[sp])) (;B[rq];W[sn];B[sm];W[so];B[rm];W[rl])) (;B[rp];W[qp] (;B[rn];W[ro] (;B[so];W[rq] (;B[sp];W[sq];B[sn];W[rm]) (;B[sq];W[sp])) (;B[rq];W[sn];B[sm];W[so];B[rm];W[rl])) (;B[ro];W[rn];B[rq];W[rs]))) (;B[ro];W[qp] (;B[rr];W[qr] (;B[rn] (;W[sr] (;B[rp];W[rq] (;B[rs];W[sp] (;B[so];W[rm] (;B[sq];W[ss] (;B[rr];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rs])) (;B[oq];W[qm] (;B[rr];W[sp]C[oops ... wrong order]) (;B[sp];W[sn]C[oops ... wrong order]) (;B[rs];W[sp]C[oops ... wrong order])) (;B[rs];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rr];B[oq];W[sp])) (;B[sp];W[qm])) (;B[oq];W[ss] (;B[rr];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[sq];W[qm]))) (;B[oq];W[ss] (;B[so];W[rm] (;B[rr]C[]) (;B[rs]C[]) (;B[sq])) (;B[rr];W[rm];B[so]) (;B[rs];W[rm];B[so]))) (;B[sq];W[rs]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[ss];W[rs])) (;B[rs] (;W[rp] (;B[sp] (;W[so] (;B[oq];W[sq];B[sn]C[You win! However P3 would have been better immediately at T6, to avoid ko.RIGHT]) (;B[sq];W[rq];B[sp];W[rm]) (;B[rq];W[sq];B[oq];W[ss];B[rr];W[rm]) (;B[sn];W[rq] (;B[so];W[rm];B[sq];W[ss] (;B[rr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;B[oq];W[ss] (;B[so];W[rm];B[sq];W[qm]) (;B[rr];W[rm];B[so];W[qm]) (;B[rs];W[rm];B[so];W[qm])))) (;W[rq];B[so]C[Very well done!RIGHT])) (;B[oq];W[rq] (;B[so];W[ss]) (;B[sp];W[ss];B[so];W[rm]))) (;W[sp] (;B[rq]C[Very well done!RIGHT]) (;B[rp];W[rq]))) (;B[sq];W[rs] (;B[ss];W[rq] (;B[sp];W[sr]) (;B[sr];W[sp];B[sr];W[rp])) (;B[rq];W[rp];B[ss];W[sp])) (;B[rq];W[rp] (;B[rs];W[sq];B[so];W[rm];B[sp];W[ss];B[rr];W[qm]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[sq];W[rs];B[ss];W[sp])) (;B[sp];W[rs] (;B[sq];W[rq]) (;B[rq];W[rp])) (;B[ss];W[rs]) (;B[so];W[rs];B[rq];W[rp]) (;B[oq];W[rs] (;B[rq];W[rp]) (;B[sq];W[rq]))) (;W[rp];B[sp] (;W[rs] (;B[sr]C[RIGHT]) (;B[sq];W[sr];B[ss];W[so];B[oq];W[sr])) (;W[sq];B[so];W[rq] (;B[oq]C[Very well done!RIGHT]) (;B[sr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;W[sr];B[rs]))) (;B[sn];W[rm];B[rn];W[sp] (;B[rp];W[rq];B[so];W[sq]) (;B[sq];W[rp];B[rs];W[qm])) (;B[rp];W[rn];B[rq];W[rs]) (;B[rm];W[rp];B[sp];W[sq] (;B[so];W[rn];B[sn];W[sm]) (;B[sn];W[qm];B[rn];W[rl]) (;B[rn];W[so];B[sn];W[rl]))) (;B[rn];W[rr]) (;B[rp];W[rn];B[rr];W[qr]) (;B[rs];W[qr];B[rn];W[rp];B[sp];W[sq];B[rr];W[sn];B[so];W[rm]) (;B[rq];W[rn];B[rr];W[qr];B[rp];W[rs]) (;B[sn];W[rr])) (;B[rs];W[qr] (;B[ro];W[qp];B[rn];W[rp];B[sp];W[sq];B[rr];W[sn];B[so];W[rm]) (;B[rp];W[qp] (;B[ro];W[rn]C[Black does not have enough space to make two eyes.]) (;B[rn];W[ro];B[so];W[rq])) (;B[rn];W[ro] (;B[so];W[rp]) (;B[rp];W[qp])) (;B[rr];W[rn]) (;B[rq];W[rn]))) (;B[rr];W[qr] (;B[qn];W[pm] (;B[ro];W[qp] (;B[rn] (;W[sr] (;B[rp];W[rq] (;B[rs];W[sp] (;B[so];W[rm] (;B[sq];W[ss] (;B[rr];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rs])) (;B[oq];W[qm] (;B[rr];W[sp]C[oops ... wrong order]) (;B[sp];W[sn]C[oops ... wrong order]) (;B[rs];W[sp]C[oops ... wrong order])) (;B[rs];W[sp] (;B[oq];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[qm];W[ql];B[sq];W[rr];B[oq];W[sp])) (;B[sp];W[qm])) (;B[oq];W[ss] (;B[rr];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[rs];W[qm];B[sq]C[You win! However S4 could have been at S1 in order to avoid ko.RIGHT]) (;B[sq];W[qm]))) (;B[oq];W[ss] (;B[so];W[rm] (;B[rr]C[]) (;B[rs]C[]) (;B[sq])) (;B[rr];W[rm];B[so]) (;B[rs];W[rm];B[so]))) (;B[sq];W[rs]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[ss];W[rs])) (;B[rs] (;W[rp] (;B[sp] (;W[so] (;B[oq];W[sq];B[sn]C[You win! However P3 would have been better immediately at T6, to avoid ko.RIGHT]) (;B[sq];W[rq];B[sp];W[rm]) (;B[rq];W[sq];B[oq];W[ss];B[rr];W[rm]) (;B[sn];W[rq] (;B[so];W[rm];B[sq];W[ss] (;B[rr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;B[oq];W[ss] (;B[so];W[rm];B[sq];W[qm]) (;B[rr];W[rm];B[so];W[qm]) (;B[rs];W[rm];B[so];W[qm])))) (;W[rq];B[so]C[Very well done!RIGHT])) (;B[oq];W[rq] (;B[so];W[ss]) (;B[sp];W[ss];B[so];W[rm]))) (;W[sp] (;B[rq]C[Very well done!RIGHT]) (;B[rp];W[rq]))) (;B[sq];W[rs] (;B[ss];W[rq] (;B[sp];W[sr]) (;B[sr];W[sp];B[sr];W[rp])) (;B[rq];W[rp];B[ss];W[sp])) (;B[rq];W[rp] (;B[rs];W[sq];B[so];W[rm];B[sp];W[ss];B[rr];W[qm]) (;B[sp];W[rs]) (;B[oq];W[rs]) (;B[sq];W[rs];B[ss];W[sp])) (;B[sp];W[rs] (;B[sq];W[rq]) (;B[rq];W[rp])) (;B[ss];W[rs]) (;B[so];W[rs];B[rq];W[rp]) (;B[oq];W[rs] (;B[rq];W[rp]) (;B[sq];W[rq]))) (;W[rp];B[sp] (;W[rs] (;B[sr]C[RIGHT]) (;B[sq];W[sr];B[ss];W[so];B[oq];W[sr])) (;W[sq];B[so];W[rq] (;B[oq]C[Very well done!RIGHT]) (;B[sr]C[Very well done!RIGHT]) (;B[rs]C[Very well done!RIGHT])) (;W[sr];B[rs]))) (;B[sn];W[rm];B[rn];W[sp] (;B[rp];W[rq];B[so];W[sq]) (;B[sq];W[rp];B[rs];W[qm])) (;B[rp];W[rn];B[rq];W[rs]) (;B[rm];W[rp];B[sp];W[sq] (;B[so];W[rn];B[sn];W[sm]) (;B[sn];W[qm];B[rn];W[rl]) (;B[rn];W[so];B[sn];W[rl]))) (;B[rn];W[ro];B[rp];W[qp] (;B[so];W[rq] (;B[sp];W[sq];B[sn];W[rm]) (;B[sq];W[sp])) (;B[rq];W[sn];B[sm];W[so];B[rm];W[rl])) (;B[rp];W[qp] (;B[rn];W[ro]) (;B[ro];W[rn]))) (;B[ro];W[qn]) (;B[rp];W[qp];B[qn];W[pm] (;B[rn];W[ro]) (;B[ro];W[rn]))) (;B[rp];W[qp] (;B[rr];W[qr];B[qn];W[pm] (;B[rn];W[ro]) (;B[ro];W[rn])) (;B[qn];W[pm] (;B[ro];W[rn];B[rr];W[qr];B[rq];W[rs]) (;B[rr];W[qr] (;B[rn];W[ro]) (;B[ro];W[rn]))) (;B[rs];W[qr];B[qn];W[pm] (;B[ro];W[rn]C[Black does not have enough space to make two eyes.]) (;B[rn];W[ro];B[so];W[rq]))) (;B[rs];W[qr] (;B[qn];W[pm] (;B[ro];W[qp];B[rn];W[rp];B[sp];W[sq];B[rr];W[sn];B[so];W[rm]) (;B[rp];W[qp] (;B[ro];W[rn]C[Black does not have enough space to make two eyes.]) (;B[rn];W[ro];B[so];W[rq])) (;B[rn];W[ro] (;B[so];W[rp]) (;B[rp];W[qp];B[so];W[rq])) (;B[rr];W[rn]) (;B[rq];W[rn])) (;B[rr];W[qn]C[Black does not have enough space to live here.]) (;B[rp];W[qp];B[qn];W[pm])) (;B[rn];W[qn]) (;B[ro];W[qn]C[Black will not have enogh space to live in the corner, this way.]) (;B[qm];W[qn]))