(;
AW [ea][eb][bc][ec][dd][fd][de][af][bf][cf][df]
AB [da][bb][db][dc][ae][be][ce]
SZ[19]
C[black to live.]
(;B[cc]
(;W[cd] C[CHOICE]
(;B[ac]
(;W[bd] C[CHOICE]
(;B[ca]
(;W[ab] C[CHOICE] ;B[aa] ;W[ad] ;B[ab] C[RIGHT correct.])
(;W[ad] C[CHOICE]
(;B[ab] C[RIGHT correct.])
(;B[aa] ;W[ab] C[oops. ko. black can do better.])
)
)
(;B[ab]
(;W[ba] C[CHOICE] C[black dies.])
(;W[ca] C[CHOICE] C[black dies.])
)
)
(;W[ca] C[CHOICE]
(;B[bd] C[RIGHT correct.])
(;B[cb] ;W[bd]
(;B[ba] ;W[ab] C[black dies.])
(;B[ab] ;W[ba] C[black dies.])
)
)
)
(;B[ca] ;W[ab]
(;B[aa] ;W[ac] C[black dies.])
(;B[ac] ;W[ad] ;B[aa] ;W[ba] C[ko. black can do better.])
)
(;B[ab]
(;W[ba] C[CHOICE] ;B[ac] ;W[bd] C[black dies.])
(;W[ca] C[CHOICE] ;B[cb] ;W[ba] ;B[ac] ;W[bd] C[black dies.])
)
)
(;W[ca] C[CHOICE]
(;B[ac] ;W[cd] ;B[bd] C[RIGHT correct.])
(;B[cd] ;W[ab]
(;B[ba] C[RIGHT correct.])
(;B[cb] ;W[ba] ;B[aa] ;W[ba]
(;B[ac] ;W[ad] C[seki. black can do better.])
(;B[ad] ;W[ac] C[seki. black can do better.])
(;B[ca] ;W[ad] ;B[aa] C[ko. black can do better.])
)
(;B[bd] ;W[ac]
(;B[ba] C[RIGHT correct.])
(;B[cb] ;W[ba] ;B[aa] ;W[ba] C[seki. black can do better.])
)
)
(;B[bd]
(;W[cd] C[CHOICE] ;B[ac] C[RIGHT correct.])
(;W[ac] C[CHOICE]
(;B[ab] C[RIGHT correct.])
(;B[cd] C[RIGHT correct.])
(;B[cb] ;W[ab]
(;B[cd] ;W[ba] ;B[aa] ;W[ba] C[seki. black can do better.])
(;B[ba] ;W[cd] C[black dies.])
)
(;B[ba] ;W[cd] ;B[cb] ;W[ab] C[black dies.])
)
)
)
)
(;B[ac] ;W[cc]
(;B[cb] ;W[cd] C[black dies.])
(;B[cd]
(;W[cb] C[CHOICE] C[black dies.])
(;W[bd] C[CHOICE] C[black dies.])
(;W[ad] C[CHOICE] C[black dies.])
)
)
(;B[cd] ;W[cc]
(;B[cb]
(;W[ad] C[CHOICE] C[black dies.])
(;W[bd] C[CHOICE] C[black dies.])
)
(;B[ac] ;W[cb] C[black dies.])
)
(;B[cb] ;W[cd] ;B[ab] ;W[ba] C[black dies.])
)