Problem 16387 goproblems.com


Author	BartTM	Created	2012-08-15
Difficulty	17 kyu (history)	Source	N/A
AVG solve time	78 sec	Stars	4.21 (14 votes)
User attempts	2189 / 5743	Collections	N/A
Genre	life and death ⓒ	Your attempts	N/A
Similar problems
Created	2012-08-15
Source	N/A
Stars	4.21 (14 votes)
Collections	N/A
Your attempts	N/A

(;AB[ac]AB[bc]AB[cc]AW[bd]AW[cd]AW[dc]AB[dd]AB[ed]AB[fc]AW[de]AB[gd]AB[ad]AW[ae]AW[bf]AW[cf]C[Best result for the corner is...?]AP[goproblems] (;W[db] (;B[ca]C[Defense nr. 1 (of 3). There are 4 moves that kill now, but only one is straightforward.CHOICE] (;W[cb];B[bb] (;W[aa]C[Black dies, so White lives.RIGHT]) (;W[da];B[aa]C[Approach move ko. Black might as well not play A19 now but tenuki instead and come back to play A19 somewhere in the endgame. So you need to play another move to prevent that.]) (;W[ba];B[aa];W[da];B[eb];W[ba]C[Just ko.]) (;W[ab];B[aa];W[da];B[eb];W[ba]C[Just ko.]) (;W[fb];B[eb]) (;W[eb];B[aa] (;W[gb];B[fb] (;W[fa];B[ea] (;W[da];B[ec]C[Ko]) (;W[ga];B[ec])) (;W[da];B[ec]C[Ko]) (;W[ea];B[fa])) (;W[fb];B[gb] (;W[da];B[fa]C[Ko]) (;W[fa];B[da];W[ea];B[ga];W[ba];B[ca])) (;W[da];B[fb]C[Ko]))) (;W[da];B[bb] (;W[cb];B[aa]C[Approach move ko. Black might as well not play A19 now but tenuki instead and come back to play A19 somewhere in the endgame. So you need to play another move to prevent that.]) (;W[aa]C[White now wins the semeai without ko.RIGHT]) (;W[ba];B[aa];W[cb];B[eb];W[ba]C[Just ko.])) (;W[bb]C[Easy does it.RIGHT]) (;W[ba];B[bb] (;W[aa]C[White wins the semeai without ko.RIGHT]) (;W[cb];B[aa];W[da];B[eb];W[ba]C[Just ko.]) (;W[da];B[aa];W[cb])) (;W[ab];B[bb] (;W[aa];B[eb] (;W[cb]C[];B[ba]) (;W[da];B[ea])) (;W[cb];B[aa]) (;W[da];B[aa];W[cb]) (;W[ba];B[aa];W[cb];B[eb];W[da];B[ea]C[Ko])) (;W[aa];B[cb]) (;W[eb];B[cb]) (;W[ea];B[bb] (;W[aa];B[eb] (;W[cb];B[ec]) (;W[da];B[fa];W[ba];B[ec]) (;W[fb];B[ec]) (;W[ba];B[ec];W[da];B[fa]) (;W[fa];B[da])) (;W[da] (;B[fa] (;W[fb];B[cb] (;W[ga];B[aa]) (;W[aa];B[eb] (;W[ga];B[ec]) (;W[ec];B[eb])) (;W[gb];B[aa])) (;W[cb] (;B[ec];W[ba]) (;B[aa];W[fb] (;B[ec];W[ga];B[eb];W[fa];B[ha]) (;B[eb]))) (;W[aa];B[eb];W[ba];B[ec])) (;B[aa];W[cb]C[Ko])) (;W[cb];B[eb]) (;W[eb];B[aa];W[cb];B[fb]C[Ko]))) (;B[ba]C[Defense nr. 2 (of 3). Two ways to kill this.CHOICE] (;W[bb];B[cb] (;W[ab];B[aa];W[da];B[eb] (;W[ca];B[ea]) (;W[bb];B[ea]) (;W[ea];B[fa]) (;W[ab];B[ea])) (;W[da];B[ab])) (;W[cb]C[];B[bb] (;W[ca]C[RIGHT]) (;W[aa]C[RIGHT]) (;W[ab]C[RIGHT]) (;W[ea];B[eb] (;W[fa];B[da]) (;W[da];B[fa]) (;W[ca];B[ec]) (;W[fb];B[ec])) (;W[eb];B[fb] (;W[ca]C[RIGHT]) (;W[ab]C[RIGHT]) (;W[aa]C[RIGHT]) (;W[ea];B[fa]) (;W[fa];B[ea] (;W[da];B[gb]) (;W[ga];B[ca];W[da];B[ec];W[ea];B[ha]) (;W[ca];B[ec]) (;W[aa];B[ec] (;W[da];B[gb]) (;W[ga];B[ha])) (;W[ab];B[ec] (;W[da];B[gb]) (;W[ga];B[ha])))) (;W[da];B[eb] (;W[ca];B[ea]) (;W[aa];B[ea]) (;W[ab];B[ea]) (;W[ea];B[fa])) (;W[fb];B[eb] (;W[ea];B[ec]) (;W[ec];B[da];W[ea];B[ca];W[eb];B[gb]) (;W[ca];B[ec]) (;W[da];B[ea]) (;W[fa];B[da];W[ea];B[gb] (;W[ec];B[ca]) (;W[ca];B[ec]))) (;W[fa];B[eb];W[ea];B[da])) (;W[ca];B[cb] (;W[ab];B[da] (;W[ea];B[eb]C[Ko]) (;W[eb];B[ea] (;W[fb];B[gb];W[fa];B[ga];W[ca];B[da]) (;W[fa];B[ga] (;W[ca];B[da] (;W[gb];B[fb];W[ha];B[ec]) (;W[ea];B[fb]C[Ko]) (;W[fb];B[gb])) (;W[fb];B[gb];W[ca];B[da])))) (;W[da];B[ab])) (;W[ab];B[cb] (;W[da]C[A semeai, avoiding ko.RIGHT]) (;W[bb];B[aa];W[da];B[eb] (;W[ca];B[ea]) (;W[bb];B[ea]) (;W[ea];B[fa]) (;W[ab];B[ea])) (;W[eb];B[fb] (;W[ca];B[da];W[ea];B[fa]C[Ko]) (;W[da];B[ec]) (;W[ea];B[ca]) (;W[bb];B[aa] (;W[ca];B[ea] (;W[bb];B[da]) (;W[ab];B[da]) (;W[da];B[ec])) (;W[da];B[ec]) (;W[ea];B[ca]) (;W[fa];B[ga]) (;W[bb];B[ec]) (;W[ab];B[ec])) (;W[aa];B[ec]) (;W[fa];B[ga])) (;W[ca];B[da] (;W[ea];B[eb]C[Ko]) (;W[eb];B[ea] (;W[fb];B[gb];W[fa];B[ga];W[ca];B[da]) (;W[fa];B[ga] (;W[ca];B[da] (;W[gb];B[fb];W[ha];B[ec]) (;W[ea];B[fb]C[Ko]) (;W[fb];B[gb])) (;W[fb];B[gb])))) (;W[ea];B[eb] (;W[ca];B[da]C[Ko]) (;W[da];B[fa]) (;W[fa];B[da]C[Ko]) (;W[bb];B[aa] (;W[ab];B[ec]) (;W[ca];B[ec]) (;W[bb];B[ec]) (;W[da];B[fa]) (;W[fb];B[ec]))) (;W[fb];B[eb])) (;W[da]C[];B[eb] (;W[cb];B[bb] (;W[ca];B[ea]) (;W[aa];B[ea]) (;W[ab];B[ea]) (;W[ea])) (;W[bb];B[cb] (;W[ab];B[aa] (;W[ca];B[ea]) (;W[bb];B[ea]) (;W[ea];B[fa]) (;W[ab];B[ea])) (;W[ca];B[ab])) (;W[ca];B[bb] (;W[ea];B[fa]) (;W[cb];B[ea]) (;W[aa];B[ea]) (;W[ab];B[ea])) (;W[ab];B[bb] (;W[ea];B[fa]) (;W[ca];B[ea]) (;W[cb];B[ea]) (;W[ec];B[fb]) (;W[fb];B[ec])) (;W[ea];B[fa]) (;W[ec];B[fb]) (;W[fb];B[ec])) (;W[eb];B[cb] (;W[ab];B[fb] (;W[ca];B[da];W[ea];B[fa]C[Ko]) (;W[da];B[ec]) (;W[ea];B[ca]) (;W[bb];B[aa] (;W[ca];B[ea] (;W[bb];B[da]) (;W[ab];B[da]) (;W[da];B[ec])) (;W[da];B[ec]) (;W[ea];B[ca]) (;W[fa];B[ga]) (;W[bb];B[ec]) (;W[ab];B[ec])) (;W[aa];B[ec]) (;W[fa];B[ga])) (;W[fb];B[gb] (;W[ab];B[ec] (;W[da];B[fa]) (;W[ea];B[ca]) (;W[ca];B[da]) (;W[bb];B[aa]) (;W[fa];B[da])) (;W[da];B[fa] (;W[ab];B[ec]) (;W[ca];B[ec])) (;W[ea];B[ab])) (;W[da];B[fb];W[ab];B[ec])) (;W[fb];B[cb] (;W[ab];B[eb]) (;W[eb];B[gb] (;W[ab];B[ec] (;W[da];B[fa]) (;W[ea];B[ca]) (;W[ca];B[da]) (;W[bb];B[aa]) (;W[fa];B[da])) (;W[da];B[fa] (;W[ab];B[ec]) (;W[ca];B[ec])) (;W[ea];B[ab])) (;W[da];B[eb] (;W[ea];B[gb] (;W[ec];B[ab]) (;W[ab];B[ec]) (;W[fa];B[ga])) (;W[ec];B[gb] (;W[ea];B[ab]) (;W[fa];B[ga];W[ea];B[ab]) (;W[ab];B[fa])) (;W[ab];B[ea])) (;W[ec];B[da];W[eb];B[gb]))) (;B[cb]C[Defense nr. 3 (of 3) featuring 3 ways to kill.] (;W[bb];B[ba] (;W[ab];B[aa];W[da];B[eb] (;W[ca];B[ea]) (;W[bb];B[ea]) (;W[ea];B[fa]) (;W[ab];B[ea])) (;W[da];B[ab])) (;W[ca];B[ba] (;W[ab];B[da] (;W[ea];B[eb]C[Ko]) (;W[eb];B[ea] (;W[fb];B[gb];W[fa];B[ga];W[ca];B[da]) (;W[fa];B[ga] (;W[ca];B[da] (;W[gb];B[fb];W[ha];B[ec]) (;W[ea];B[fb]C[Ko]) (;W[fb];B[gb])) (;W[fb];B[gb])))) (;W[da];B[ab])) (;W[da] (;B[eb]C[CHOICE] (;W[ca];B[ab];W[ba];B[ea] (;W[bb]C[RIGHT]) (;W[aa]C[RIGHT])) (;W[ba]C[RIGHT]) (;W[ab]C[RIGHT]) (;W[bb];B[ba] (;W[ab];B[aa]) (;W[ca];B[ab])) (;W[aa];B[ca]) (;W[ea];B[fa])) (;B[ab]C[CHOICE];W[ba]C[RIGHT])) (;W[ba]C[RIGHT]) (;W[ab];B[da] (;W[ea];B[ba];W[ca]C[Ko]) (;W[ba];B[eb]) (;W[ca];B[ba] (;W[ea];B[eb]C[Ko]) (;W[eb];B[ea] (;W[fb];B[gb];W[fa];B[ga];W[ca];B[da]) (;W[fa];B[ga] (;W[ca];B[da] (;W[gb];B[fb];W[ha];B[ec]) (;W[ea];B[fb]C[Ko]) (;W[fb];B[gb])) (;W[fb];B[gb])))) (;W[bb]C[RIGHT]) (;W[aa];B[eb]) (;W[eb];B[ba];W[ea];B[fb];W[ca]C[Ko])) (;W[fb];B[eb] (;W[ea];B[ec];W[da];B[gb]) (;W[da];B[ea]) (;W[fa];B[da]) (;W[ec];B[da])) (;W[eb];B[ba] (;W[ab]) (;W[fb];B[gb] (;W[ab];B[ec] (;W[da];B[fa]) (;W[ea];B[ca]) (;W[ca];B[da]) (;W[bb];B[aa]) (;W[fa];B[da])) (;W[da];B[fa] (;W[ab];B[ec]) (;W[ca];B[ec])) (;W[ea];B[ab])) (;W[da];B[fb];W[ab])))) (;W[cb];B[db]) (;W[eb];B[db]) (;W[da];B[db]) (;W[ff];B[db]C[Nice wall facing down. Pity you lost the corner though.]) (;W[gf];B[db]C[Black may try to separate G14 from the rest of your stones later. But rescueing the corner is bigger.]) (;W[ba];B[db]) (;W[ec];B[eb]) (;W[bb];B[db]) (;W[ca];B[db]) (;W[fe];B[db]) (;W[ee];B[db]) (;W[ef];B[db]))