(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2] RU[Japanese]SZ[4]KM[0.00] PW[Weiß]PB[Schwarz]AW[bb][cb][db]AB[ca][bc][cc][dc][bd]C[White to play - what's the best he can do?]PL[W] (;W[ab]CR[ab] (;B[ac]CR[ac] ;W[ba]CR[ba]C[White wins by one point RIGHT]) (;B[ba]CR[ba] ;W[ac]CR[ac] ;B[aa]CR[aa] (;W[cd]CR[cd] ;B[dd]CR[dd] ;W[da]CR[da] ;B[ba]CR[ba] ;W[ad]CR[ad]C[White wins big.]) (;W[da]CR[da] ;B[ba]CR[ba] (;W[cd]CR[cd] ;B[aa]CR[aa] ;W[ca]CR[ca] ;B[ba]CR[ba]C[This is a 5 point win for White, but with this first black move (b4), he can do even better.]) (;W[dd]CR[dd] ;B[ca]CR[ca] ;W[aa]CR[aa] ;B[ba]CR[ba]C[This is a 5 point win for White but after this first move by Black (b4), White can do even better.])))) (;W[ac]CR[ac] ;B[ab]CR[ab] (;W[ba]CR[ba] ;B[ad]CR[ad] (;W[da]CR[da] ;B[ac]CR[ac] ;W[cd]CR[cd] ;B[dd]CR[dd]C[Seki, Black wins by one point (two prisoners against one).]) (;W[cd]CR[cd]C[Seki, Black wins by one point (two prisoners against one).])) (;W[aa]CR[aa] ;B[ba]CR[ba] (;W[ab]CR[ab] ;B[ad]CR[ad]C[Black wins!]) (;W[da]CR[da] ;B[ba]CR[ba] (;W[ca]CR[ca] ;B[ad]CR[ad]C[Black wins!]) (;W[ab]CR[ab] ;B[ad]CR[ad]C[Black wins!]) (;W[cd]CR[cd] ;B[ab]CR[ab]C[Black wins!]) (;W[dd]CR[dd] ;B[ab]CR[ab]C[Black wins!])))))