(;AB[cc]AB[cd]AB[dd]AB[dc]AW[ab]AW[bb]AW[ba]C[Black to kill. *NOTE* This is a symmetric position: please do not play on the left. Only variations starting on top are covered.]AP[goproblems] (;B[ee];W[eb]C[FORCE] (;B[da];W[db];B[cb];W[ca];B[fb];W[ec];B[fc];W[be] (;B[ad];W[bd];B[bc]C[White cannot play A17. Well done !RIGHT]MA[ac]) (;B[bc];W[ac];B[ad]C[White cannot play B16. Well done !RIGHT]MA[bd]) (;B[bd];W[ad];B[bf];W[ce];B[cf];W[de];B[df];W[ed];B[ae];W[fd]C[White escapes.]) (;B[bf]C[NOTTHIS])) (;B[db];W[da];B[fb];W[gb] (;B[fa];W[fc];B[ec];W[ga];B[ea];W[eb]) (;B[ec];W[fa]C[Escape through ko.]) (;B[fc];W[fa])) (;B[cb];W[ca] (;B[da];W[db];B[fb];W[ec];B[fc];W[be] (;B[ad];W[bd];B[bc]C[White cannot play A17. Well done !RIGHT]MA[ac]) (;B[bc];W[ac];B[ad]C[White cannot play B16. Well done !RIGHT]MA[bd]) (;B[bd];W[ad];B[bf];W[ce];B[cf];W[de];B[df];W[ed];B[ae];W[fd]C[White escapes.]) (;B[bf]C[NOTTHIS])) (;B[db];W[da];B[fb];W[gb] (;B[ec];W[ea];B[fc];W[fa]) (;B[fa];W[fc]) (;B[fc];W[fa]))) (;B[ca];W[cb];B[db];W[da];B[fb];W[gb];B[ec];W[fa])) (;B[cb];W[be] (;B[ad];W[bd];B[bc];W[ac];B[bf];W[ce]C[White escapes.]) (;B[bd];W[ad]C[];B[bf];W[ce]C[White escapes.]) (;B[bc];W[ac];B[ad];W[bd];B[bf];W[ce]C[White escapes.]) (;B[bf]C[NOTTHIS])))