Problem 21 goproblems.com


Author	adum	Created	1999-08-03
Difficulty	4 dan (history)	Source	BGJ 66
AVG solve time	26 sec	Stars	4.21 (52 votes)
User attempts	2545 / 23877	Collections	Symmetrical, Corner based
Genre	life and death ⓒ	Your attempts	N/A
Similar problems
Created	1999-08-03
Source	BGJ 66
Stars	4.21 (52 votes)
Collections	Symmetrical, Corner based
Your attempts	N/A

(;AW[ea]AW[fa]AW[eb]AW[dc]AW[cd]AW[dd]AW[ed]AW[fd]AW[ae]AW[be]AW[de]AW[fe]AW[af]AW[df]AW[ef]AB[ga]AB[fb]AB[gb]AB[cc]AB[ec]AB[fc]AB[gd]AB[ce]AB[ge]AB[bf]AB[cf]AB[ff]AB[gf]AB[ag]AB[bg]AB[dg]AB[eg]AB[fg]C[Black to play and kill white unconditionally]SZ[19]GM[1]FF[3]RU[Japanese]HA[0]KM[5.5]PW[White]PB[Black]GN[White (W) vs. Black (B)]DT[1999-07-28]SY[Cgoban 1.9.2]TM[30:00(5x1:00)] (;B[bc];W[cb] (;B[bd];W[db]) (;B[bb];W[bd] (;B[ca];W[db];B[ac];W[da];B[ba];W[aa]) (;B[db];W[da];B[ba];W[ac];B[ab];W[ad]) (;B[ba];W[db];B[ca];W[ac];B[ab];W[ad]))) (;B[bb];W[cb] (;B[ca];W[bc] (;B[ac];W[bd];B[db]C[snapback city.RIGHT]) (;B[db];W[ac] (;B[bd];W[ad] (;B[cc]C[ko. you can do better.]) (;B[ab];W[cc])) (;B[cc];W[bd])) (;B[ab];W[ac])) (;B[bc];W[bd] (;B[ca];W[db] (;B[ac];W[da];B[ba];W[aa]) (;B[ba];W[ac];B[ab];W[ad])) (;B[ba];W[db] (;B[ca];W[ac];B[ab];W[ad]) (;B[ac];W[ca]))) (;B[bd];W[bc];B[ac];W[ca];B[db];W[da];B[cc]C[only ko. you can do better.])) (;B[cb];W[bc] (;B[db];W[bd]) (;B[bb];W[db] (;B[bd];W[ad];B[ab];W[ca];B[ba];W[da]) (;B[ac];W[bd] (;B[ca];W[ad];B[ab];W[ba]) (;B[ab];W[ca];B[ba];W[da])) (;B[ab];W[ca] (;B[ac];W[bd];B[ba];W[da]) (;B[bd];W[ad];B[ba];W[da])))) (;B[ca];W[db] (;B[bc];W[cb] (;B[bb];W[bd] (;B[ac];W[da] (;B[ad];W[ba]) (;B[ba];W[ab])) (;B[ba];W[ac];B[ab];W[ad])) (;B[bd];W[bb])) (;B[bd] (;W[bc];B[bb];W[ad] (;B[cb];W[ab];B[aa]C[ko. you can do better.]) (;B[ab];W[cb];B[ac];W[bd]) (;B[ac];W[ab])) (;W[cb];B[bb];W[bc];B[ac]) (;W[bb] (;B[cb];W[bc]) (;B[bc];W[cb]))) (;B[bb];W[bd] (;B[bc];W[ac];B[ab];W[cb];B[ad];W[ba];B[aa]) (;B[cb];W[bc];B[ac];W[da];B[ab];W[ba]) (;B[ac];W[bc];B[cb];W[aa];B[da];W[ab];B[ba];W[ab];B[aa];W[ab])) (;B[cb];W[bc] (;B[bb];W[ab];B[bd];W[ad];B[aa]C[ko. you can do better.]) (;B[bd];W[ad];B[bb];W[ab];B[aa]C[ko. you can do better.]))) (;B[ac];W[bd]C[black is lost. for variations, try the mirror of this move.]) (;B[db];W[cb] (;B[da];W[bc];B[ac];W[ab]) (;B[bb];W[bc] (;B[ca];W[ac]C[ko] (;B[bd];W[ad] (;B[cc]C[ko. you can do better.]) (;B[ab];W[cc])) (;B[cc];W[bd])) (;B[ac];W[da];B[bd];W[cc]))) (;B[bd];W[cb] (;B[bc];W[bb] (;B[ab];W[ba]) (;B[db];W[da];B[ab];W[ba])) (;B[bb];W[bc] (;B[ca];W[ad]) (;B[ac];W[ca]C[ko];B[db];W[da];B[cc]C[only ko. you can do better.]))))