(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2] RU[Japanese]SZ[4]KM[0.00] PW[Weiß]PB[Schwarz]AW[aa][da][bb][cb]AB[ac][dc][bd][cd]C[Black to move - what's the best he can do?] (;B[ab]CR[ab] (;W[bc]CR[bc] (;B[ba]CR[ba] ;W[cc]CR[cc]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;B[ad]CR[ad] (;W[cc]CR[cc] ;B[ba]CR[ba]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;W[ba]CR[ba] ;B[db]CR[db]C[Black wins.]))) (;W[cc]CR[cc] (;B[ba]CR[ba] ;W[bc]CR[bc]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;B[bc]CR[bc] ;W[ba]CR[ba]C[Seki & jigo.]) (;B[dd]CR[dd] ;W[bc]CR[bc] ;B[ba]CR[ba]C[Seki, Black wins by one point (the prisoner). RIGHT])) (;W[ba]CR[ba] ;B[db]CR[db]C[Black wins.])) (;B[db]CR[db] (;W[cc]CR[cc] (;B[ca]CR[ca] ;W[bc]CR[bc]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;B[dd]CR[dd] (;W[bc]CR[bc] ;B[ca]CR[ca]C[Seki, Black wins by one point (the prisoner) RIGHT]) (;W[ca]CR[ca] ;B[ab]CR[ab]C[Black wins.]))) (;W[bc]CR[bc] (;B[ca]CR[ca] ;W[cc]CR[cc]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;B[cc]CR[cc] ;W[ca]CR[ca]C[Seki & jigo.]) (;B[ad]CR[ad] ;W[cc]CR[cc] ;B[ca]CR[ca]C[Seki, Black wins by one point (the prisoner). RIGHT])) (;W[ca]CR[ca] ;B[ab]CR[ab]C[Black wins.])) (;B[bc]CR[bc] ;W[cc]CR[cc] ;B[ab]CR[ab] ;W[ba]CR[ba]C[Seki & jigo.]) (;B[cc]CR[cc] ;W[bc]CR[bc] ;B[db]CR[db] ;W[ca]CR[ca]C[Seki & jigo.]) (;B[ba]CR[ba] (;W[bc]CR[bc] ;B[ab]CR[ab] ;W[cc]CR[cc]C[Seki, Black wins by one point (the prisoner) RIGHT]) (;W[ab]CR[ab] ;B[db]CR[db] (;W[cc]CR[cc] ;B[ca]CR[ca] ;W[da]CR[da] ;B[ca]CR[ca]C[Black wins!]) (;W[ca]CR[ca] (;B[cc]CR[cc]C[Black wins!]) (;B[bc]CR[bc]C[Black wins!])))) (;B[ca]CR[ca] (;W[cc]CR[cc] ;B[db]CR[db] ;W[bc]CR[bc]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;W[db]CR[db] ;B[ab]CR[ab] (;W[ba]CR[ba] (;B[bc]CR[bc]C[Black wins!]) (;B[cc]CR[cc]C[Black wins!])) (;W[bc]CR[bc] ;B[ba]CR[ba] ;W[aa]CR[aa] ;B[ba]CR[ba]C[Black wins!]) (;W[cc]CR[cc] ;B[ba]CR[ba] ;W[aa]CR[aa] ;B[bc]CR[bc] ;W[dd]CR[dd] ;B[ba]CR[ba]C[Black wins!]))))