(;GM[1]FF[3]
RU[Chinese]GC[simple problem, coposed by jonathan Cano.
]SZ[19]HA[0]
KM[5.5]
PW[White]
PB[Black]
GN[White (W) vs. Black (B)]
DT[2000-05-21]
SY[Cgoban 1.9.10]TM[30:00(5x1:00)];PL[1]
AW[ea][fb][gb][cc][dc][ec][ad][bd][cd][gd]AB[bb][cb][db][eb][ac][bc]
C[Black to play and live.
]
(;B[aa];W[da];B[ca]C[RIGHT. Black lives unconditionally.
])
(;B[ab];W[da];B[ca];W[fa]C[one eye, black is dead.
])
(;B[ba];W[da]C[one eye, black is dead
])
(;B[ca];W[aa]C[one eye, black is dead.
])
(;B[da];W[ba]
(;B[ca];W[aa]C[one eye, black is dead.
])
(;B[aa];W[ab]
C[Ko at A1. If white wins the ko (and connects at A1, black dies. (variation follows)
]
;B[fa];W[aa];B[ca];W[aa]C[one eye, black is dead.
])
)
)