(;AP[goproblems]AB[cb]AB[cc]AB[bd]AW[cd]AW[dc]AW[ec]AW[fb]AW[ce]AW[cg]AW[gc]C[White to kill.](;W[be](;B[ac]C[CHOICE](;W[bb];B[ba](;W[ab];B[db](;W[da]C[RIGHT])(;W[eb];B[da]))(;W[bc];B[ab])(;W[db];B[ab])(;W[ae];B[ab];W[ad];B[bc]))(;W[db];B[bb])(;W[ba];B[bb];W[ca];B[db](;W[eb];B[da])(;W[da];B[ea];W[eb];B[aa]))(;W[ae](;B[ba](;W[ad];B[bc];W[ab]C[RIGHT])(;W[db];B[ab])(;W[bc];B[bb](;W[ad];B[db](;W[da]C[RIGHT])(;W[bc]C[NOTTHIS]))(;W[ab];B[aa];W[ad]C[RIGHT]))(;W[ab];B[db](;W[bb];B[da])(;W[da]C[RIGHT])(;W[ad]C[RIGHT])))(;B[bb];W[ad];B[aa](;W[ca]C[RIGHT])(;W[bc]C[NOTTHIS])))(;W[da];B[bb])(;W[ab];B[bb];W[ae];B[aa];W[ad])(;W[ad](;B[ae];W[bb]C[RIGHT])(;B[bb]C[Now you're just being silly.CHOICE](;W[ae]C[RIGHT])(;W[bc]C[Ko is not the answer!]))))(;B[bb]C[CHOICE](;W[ad];B[ac](;W[bc]C[Ko is not the answer.])(;W[ae];B[aa](;W[ca]C[RIGHT])(;W[bc]C[NOTTHIS])))(;W[ae];B[ac];W[ad];B[aa](;W[bc]C[NOTTHIS])(;W[ca]C[RIGHT]))(;W[ac];B[ad](;W[ae];B[bc](;W[ca];B[db];W[da];B[ab])(;W[ab];B[aa];W[ca]C[RIGHT]))(;W[ab];B[db](;W[ae];B[bc];W[da]C[RIGHT])(;W[da];B[ca];W[aa]C[RIGHT])(;W[eb](;B[aa](;W[ba];B[ca];W[ae]C[RIGHT])(;W[da];B[ca]))(;B[da];W[ba](;B[ca](;W[ae]C[RIGHT])(;W[ea];B[aa]))(;B[bc](;W[ae]C[RIGHT])(;W[ea]C[RIGHT])))))(;W[ca];B[db];W[da];B[ea](;W[eb];B[ab])(;W[ae];B[bc];W[eb];B[ab]))))(;B[ab](;W[ba];B[ad];W[ca]C[RIGHT])(;W[bc];B[ad];W[ba];B[bb])(;W[ad];B[ba];W[bc]C[RIGHT])))(;W[db];B[bb]C[Black is alive, see problem 4798.])(;W[ac];B[ab];W[bb];B[ba];W[aa](;B[bc](;W[ca];B[db]C[Life in double ko.])(;W[ab]C[Hard to find move! B17 was a mistake by Black.]))(;B[db]C[CHOICE](;W[ca];B[bc]C[Life in double ko.])(;W[da];B[ab])(;W[bc];B[ab])))(;W[ba];B[bb]C[CHOICE](;W[ac];B[be](;W[ca];B[db](;W[da];B[ea])(;W[ab];B[da]))(;W[bf];B[ab];W[ca];B[db])(;W[ab];B[ca](;W[aa];B[bf];W[bg];B[af])(;W[db];B[ad])))(;W[be];B[ac](;W[ae];B[aa](;W[ab];B[ca];W[ad];B[bc])(;W[ad];B[bc];W[ab];B[ca]))(;W[aa];B[ca];W[ae];B[ad]))(;W[ab];B[ac];W[ca];B[da])(;W[ca](;B[ac];W[be];B[db](;W[eb];B[da])(;W[da];B[ea];W[eb];B[aa]))(;B[db]))(;W[db];B[ca](;W[ac];B[ab])(;W[be];B[ac])))(;W[bc];B[bb];W[ac];B[ab])(;W[ad];B[be](;W[bf];B[ac](;W[bb];B[ba];W[ab];B[ae])(;W[ab];B[ae])(;W[db];B[ca]))(;W[bc];B[bb])(;W[ab];B[bc];W[ac];B[bf])(;W[ac];B[bc];W[ab];B[bf]))(;W[ab](;B[be]C[CHOICE](;W[bf];B[ac](;W[ae];B[bb];W[af];B[aa])(;W[bb];B[ae];W[bc];B[ba]C[Ko is not the answer.]))(;W[bc];B[bb])(;W[bb];B[bg];W[bc]C[Arguably this counts, but there are better lines.RIGHT])(;W[ba];B[bb];W[ac];B[ca]))(;B[ac];W[bb](;B[be];W[bc];B[ba];W[ad];B[ae];W[db]C[RIGHT])(;B[ba];W[be];B[db];W[da]C[RIGHT]))(;B[bb];W[ac];B[db](;W[be]C[RIGHT])(;W[ae]C[RIGHT])(;W[da]C[RIGHT])))(;W[bb];B[ab](;W[ba];B[bc])(;W[ac];B[ba];W[aa](;B[bc];W[ab]C[Nice! Hard to find. Black's B17 was a mistake.])(;B[db]C[CHOICE](;W[ca];B[bc]C[Life in double ko.])(;W[bc];B[ab])(;W[da];B[ab])))(;W[be];B[ad])(;W[ca];B[bc])(;W[bc];B[ba]))(;W[ae](;B[ac]C[CHOICE](;W[be];B[bb];W[ad];B[aa];W[ca]C[RIGHT])(;W[bb];B[ba];W[ab];B[db];W[da]C[RIGHT]))(;B[ab](;W[ba];B[ad];W[ca]C[RIGHT])(;W[ad](;B[ba](;W[bc];B[db];W[da]C[RIGHT])(;W[db];B[bc]))(;B[be];W[bf];B[ba];W[bc]C[RIGHT]))(;W[bc];B[ad]))(;B[bc]C[Death in gote.RIGHT])(;B[bb]C[CHOICE](;W[ad];B[ac];W[be];B[aa];W[ca]C[RIGHT])(;W[ac];B[ad](;W[be];B[bc];W[ab];B[aa];W[ca]C[RIGHT])(;W[ab];B[db];W[da]C[RIGHT]))(;W[be];B[db];W[ad];B[ac](;W[da]C[RIGHT])(;W[aa]C[RIGHT])(;W[ba]C[Kills with double ko, but can be better.])))(;B[ad];W[ab];B[be];W[bf];B[af];W[ag];B[bb];W[ac];B[db];W[da]C[RIGHT])(;B[be];W[bf];B[ac](;W[bb];B[ba];W[ab];B[db];W[da]C[RIGHT])(;W[af];B[bb];W[ad];B[db](;W[da];B[aa];W[ca]C[RIGHT])(;W[aa]C[RIGHT]))))(;W[af](;B[ae]C[Fancy move! Does it work?CHOICE](;W[ab];B[ac](;W[bb];B[be];W[bc];B[ba])(;W[be];B[bb];W[ad];B[aa];W[ca];B[ae]))(;W[ac];B[ab](;W[ba];B[bb](;W[be]C[RIGHT])(;W[ca];B[db](;W[da];B[ea];W[be]C[RIGHT])(;W[be]C[RIGHT]))(;W[db];B[ca];W[be]C[RIGHT]))(;W[bb];B[ba])(;W[be];B[bc](;W[ad];B[ba])(;W[ba]C[RIGHT])))(;W[be];B[ac];W[bb](;B[bf];W[bc];B[ag];W[ab]C[RIGHT])(;B[ba]C[CHOICE];W[ab];B[db];W[da]C[RIGHT]))(;W[bc];B[bb])(;W[bb];B[ab](;W[be];B[ba])(;W[ac];B[ba])(;W[bc];B[ba])(;W[ba];B[bc]))(;W[db];B[ac](;W[bb];B[ba](;W[ab];B[be])(;W[be];B[ab]))(;W[be];B[bb])(;W[ab];B[bb];W[be];B[aa])))(;B[ac](;W[ae](;B[bb];W[ad]C[RIGHT])(;B[ba](;W[ab]C[RIGHT])(;W[ad](;B[ab];W[bc]C[RIGHT])(;B[bc];W[ab]C[RIGHT]))))(;W[bb];B[ba];W[ab];B[be];W[ae]C[RIGHT]))(;B[be];W[bf];B[ac](;W[ae]C[RIGHT])(;W[bb];B[ba](;W[ab];B[ae])(;W[ae];B[ab])))))
ldan