(;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!]))))