(;AW[da][db][dc][cd][ed][ce][af][bf][cf]AB[ca][cb][cc][bd][be]C[black to live
]
(;B[ac]
(;W[ae]C[CHOICE]
(;B[bb]
;W[ad]
(;B[aa]C[RIGHT
])
(;B[bc]
;W[aa]))
(;B[ad]
;W[ab])
(;B[ab]CR[ab]
;W[ba]CR[ba]
(;B[ad]CR[ad]
;W[bb]CR[bb])
(;B[bb]CR[bb]
;W[ad]CR[ad]))
(;B[ba]CR[ba]
;W[ab]CR[ab]
;B[bb]CR[bb]
;W[ad]CR[ad])
(;B[aa]CR[aa]
;W[bb]CR[bb]))
(;W[bb]CR[bb]C[CHOICE]
(;B[ba]CR[ba]
;W[ab]CR[ab]
(;B[ae]CR[ae]C[RIGHT])
(;B[bc]CR[bc]
;W[ae]CR[ae]))
(;B[ab]CR[ab]
;W[ba]CR[ba]
(;B[bc]CR[bc]
;W[ae]CR[ae])
(;B[ae]CR[ae]
;W[bc]CR[bc]))))
(;B[bb]
;W[ac]
(;B[ae]
;W[bc])
(;B[ab]
;W[ae]
(;B[ad]
;W[bc])
(;B[bc]CR[bc]
;W[ad]CR[ad]))
(;B[ad]
;W[ab]
(;B[bc]
;W[aa])
(;B[aa]
;W[ba]C[Only ko.]))
(;B[bc]CR[bc]
;W[ab]CR[ab]
(;B[ae]CR[ae]
;W[aa]CR[aa]C[Black dies (the infamous 'bent four in the corner')])
(;B[aa]CR[aa]
;W[ba]CR[ba]C[Black does not have enough liberties to play A16, so this is only ko.])
(;B[ad]CR[ad]
;W[aa]CR[aa]C[Dead])))
(;B[ab]
;W[bc]
(;B[ac]
;W[ad]
;B[bb]
;W[ae])
(;B[bb]
;W[ad]
;B[ac]
;W[ae])
(;B[ad]CR[ad]
;W[bb]CR[bb])
(;B[ba]CR[ba]
;W[ad]CR[ad]))
(;B[bc]CR[bc]
;W[ab]CR[ab]C[No room left for two eyes.])
(;B[ae]CR[ae]
;W[bc]CR[bc]))