(;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][ca][cb][db][dc]AB[bc][cc][bd][cd]C[Black to play - what's the best he can do?]PL[B] (;B[bb]CR[bb] (;W[ba]CR[ba] ;B[ab]CR[ab] ;W[ac]CR[ac]C[Now, please capture :)] ;B[ad]CR[ad]C[Seki, Black wins by one point (the prisoner). RIGHT]) (;W[ab]CR[ab] ;B[ba]CR[ba] ;W[ac]CR[ac] ;B[ad]CR[ad] ;W[ab]CR[ab] ;B[dd]CR[dd]C[White is lost.])) (;B[ab]CR[ab] ;W[bb]CR[bb] (;B[ba]CR[ba] ;W[ac]CR[ac]C[White wins!]) (;B[ac]CR[ac] ;W[ba]CR[ba]C[Seki & jigo!])) (;B[ac]CR[ac] ;W[bb]CR[bb] ;B[ab]CR[ab] ;W[ba]CR[ba]C[Seki & jigo.]))