(;AW[ba]AW[ab]AW[bb]AW[cc]AB[db]AB[bd]AB[dd]C[Black to kill white]C[This is fun problem I encounted when I started learning GO. It demonstrates a commonly usedprinciple.]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[ee]
(;W[eb]
(;B[fb]
(;W[da]
(;B[ec]
(;W[ea]
(;B[dc];W[gb]
(;B[fa];W[ca]
(;B[fc]C[RIGHT])
(;B[gc]C[RIGHT]))
(;B[ca];W[cb];B[fa]C[RIGHT]))
(;B[fa];W[ca];B[dc]C[RIGHT])
(;B[ca];W[cb];B[dc];W[gb];B[fa]C[RIGHT]))
(;W[fa];B[ga]C[RIGHT]))
(;B[dc];W[gb]
(;B[ec];W[fa]C[white escapes via ko])
(;B[fa];W[fc];B[ec];W[ga]C[snapback])
(;B[fc];W[fa]C[white escapes])))
(;W[ec];B[dc];W[da];B[fc];W[ed];B[fd];W[be];B[bf];W[ce];B[cd];W[ad];B[cf];W[de];B[df]C[RIGHT])
(;W[dc];B[ec];W[ea];B[fa]C[RIGHT])
(;W[ea];B[dc];W[da]
(;B[fc]C[RIGHT])
(;B[ec]C[RIGHT];W[gb]
(;B[fa];W[ca]
(;B[fc]C[RIGHT])
(;B[gc]C[RIGHT]))
(;B[ca];W[cb];B[fa]C[RIGHT]))
(;B[fa]C[RIGHT])))
(;B[ec];W[fb]
(;B[dc];W[da]C[white escapes])
(;B[da];W[dc]C[white captures two black stones and live]))
(;B[cb];W[da];B[dc];W[ca];B[fb];W[gb]C[the best black can do is ko])
(;B[dc];W[da];B[fb];W[gb]
(;B[ec];W[fa]C[white escapes via ko])
(;B[fa];W[fc];B[ec];W[ga]C[snapback])
(;B[fc];W[fa]C[white escapes]))
(;B[bc];W[dc])
(;B[cd];W[dc]))
(;W[dc];B[ec];W[eb];B[fb]C[RIGHT]TR[eb];W[ea];B[fa]C[RIGHT])
(;W[be]
(;B[bf]
(;W[ad]
(;B[ce]
(;W[ae];B[cd];W[bg];B[af];W[ac]
(;B[cf]C[RIGHT])
(;B[df]C[RIGHT]))
(;W[af];B[ag]C[RIGHT]))
(;B[cd];W[bg]
(;B[ce];W[af]C[white escapes via ko])
(;B[af];W[cf];B[ce];W[ag]C[snapback])
(;B[cf];W[af]C[white escapes])))
(;W[ce];B[cd];W[ad];B[cf];W[de];B[df];W[eb];B[fb];W[ec];B[dc];W[da];B[fc];W[ed];B[fd]C[RIGHT])
(;W[cd];B[ce]C[RIGHT])
(;W[ae];B[cd];W[ad];B[cf]C[RIGHT]))
(;B[ce];W[bf]
(;B[cd];W[ad]C[white escapes])
(;B[ad];W[cd]C[white captures two black stones and lives]))
(;B[cd];W[ad];B[bf];W[bg]C[the best black can do it ko]
(;B[ce];W[af]C[white escapes via ko])
(;B[af];W[cf];B[ce];W[ag]C[snapback])
(;B[cf];W[af]C[white escapes]))
(;B[bc];W[ad];B[cd];W[ac];B[bf];W[bg]C[the best black can do is ko]))
(;W[cd];B[ce];W[be];B[bf]C[RIGHT]))
(;B[cd];W[eb]
(;B[dc];W[da];B[fc];W[gb]C[White escaped. While black may still kill white, depending on the rest of the board,black can do better.])
(;B[da];W[dc];B[ec];W[fb]C[white escapes])
(;B[ec];W[fb]
(;B[da];W[dc])
(;B[dc];W[da])))
(;B[dc];W[be]
(;B[cd];W[ad];B[cf];W[bg]C[black can do better])
(;B[ad];W[cd];B[ce];W[bf])
(;B[ce];W[bf]
(;B[ad];W[cd])
(;B[cd];W[ad])))
(;B[ce]C[see variation on C16])
(;B[ec]C[see variation on D17])
(;B[de];W[eb];B[dc];W[da];B[fb];W[gb]
(;B[ec];W[fa]C[escape via ko])
(;B[fc];W[fa]C[white escapes])
(;B[fa];W[fc];B[ec];W[ga]C[sanpback]))
(;B[ed]C[see variation on D15])
(;B[bc];W[eb]
(;B[cb];W[da];B[ec];W[fb]C[white escapes])
(;B[ec];W[fb];B[cb];W[da])
(;B[dc];W[da])
(;B[da];W[dc];B[ec];W[cb];B[fb];W[ed];B[fc];W[cd]C[white escapes]))
(;B[cb]C[see variation on B17]))