There are a few places where black could start a ko(to his disadvantage), instead of the actual move which allows white to kill, but otherwise the problem would suck.
(;
;AB[bb][db][eb][fb][ec][cd][dd][be][bf][cf][cg]
AW[gb][ib][bc][gc][bd][ed][ce][de][ee][df][dg][ch][dh]
C[White to kill.]
(;W[ae];B[cc])
(;W[ba];B[cb])
(;W[ab];B[cb])
(;W[cc];B[cb];W[dc];B[ab])
(;W[cb];B[ca];W[cc];B[dc]
(;W[ab];B[ba]
(;W[ac];B[da])
(;W[da];B[ea];W[ac];B[ae]C[notice black could play ko at a14, but for the problem he doesn't.]
;W[bg];B[bh];W[ag];B[ah];W[bi];B[af]
(;W[ag];B[bg];W[ai]C[RIGHT])
(;W[bg];B[ag];W[ai]C[RIGHT])
)
)
(;W[da];B[ea]
(;W[ab];B[ba];W[ac];B[ae]C[notice black could play ko at a14, but for the problem he doesn't.]
;W[bg];B[bh];W[ag];B[ah];W[bi];B[af]
(;W[ag];B[bg];W[ai]C[RIGHT])
(;W[bg];B[ag];W[ai]C[RIGHT])
)
(;W[ba];B[aa];W[ac];B[ae]C[notice black could play ko at a14, but for the problem he doesn't.]
;W[bg];B[bh];W[ag];B[ah];W[bi];B[af]
(;W[ag];B[bg];W[ai]C[RIGHT])
(;W[bg];B[ag];W[ai]C[RIGHT])
)
)
(;W[ba];B[aa]
(;W[ac];B[ae]C[notice black could play ko at a14, but for the problem he doesn't.]
;W[bg];B[bh];W[ag];B[ah];W[bi];B[af]
(;W[ag];B[bg];W[ai]C[RIGHT])
(;W[bg];B[ag];W[ai]C[RIGHT])
)
(;W[da];B[ea];W[ac];B[ae]C[notice black could play ko at a14, but for the problem he doesn't.]
;W[bg];B[bh];W[ag];B[ah];W[bi];B[af]
(;W[ag];B[bg];W[ai]C[RIGHT])
(;W[bg];B[ag];W[ai]C[RIGHT])
)
)
)
)