Happened to me in a game... Reduce the black position as much as possible!
(;AW[ia]AW[ja]AW[db]AW[jb]AW[kb]AW[ec]AW[kc]AW[bd]AW[cd]AW[dd]AW[ed]AW[id]AW[jd]AW[fe]AW[he]AB[ha]AB[cb]AB[eb]AB[ib]AB[cc]AB[dc]AB[fc]AB[hc]AB[ic]AB[jc]AB[fd]AB[hd]CA[UTF-8]
(;W[fb]
(;B[da]
(;W[gb]
(;B[fa]
(;W[hb];B[bc]C[Big reduction in sente for white! (If B tenuki, W can play b18 and make a ko out of the whole corner) RIGHT])
(;W[gd]
(;B[bc]C[Big reduction in sente! RIGHT])
(;B[ga];W[bb];B[hb];W[gc];B[bc];W[ac];B[ab];W[aa];B[ba];W[ca]C[Trying like this makes it even worse for B.]))
(;W[gc];B[ga];W[gd];B[bc]C[Not bad, though a little more is possible! RIGHT])
(;W[ga];B[hb]C[Only ko.]))
(;B[ga];W[fa])
(;B[hb];W[gd])
(;B[gc];W[hb]))
(;W[ga];B[gb];W[hb];B[fa]C[A small reduction in gote.])
(;W[fa];B[gb]C[W fails])
(;W[gc]
(;B[gb];W[gd];B[bc]C[Big reduction in sente! RIGHT])
(;B[gd];W[gb]
(;B[ge];W[gf])
(;B[fa];W[ge])))
(;W[gd]
(;B[gb]
(;W[gc];B[bc]C[Big reduction in sente! (If B tenuki, W can play B18 and make a ko out of the whole corner.) RIGHT])
(;W[fa];B[gc]C[Does not work...]))
(;B[gc];W[gb];B[ge];W[hb])))
(;B[gb];W[ea];B[gd];W[ga]C[Even worse for b, he's dead in the corner now and the other group doesnt live yet. (ko)])
(;B[ea]C[This also doesn't help];W[gb]
(;B[fa];W[ga]
(;B[hb];W[da])
(;B[da];W[gd];B[bc]C[Big reduction in sente - if B misses to play b17 W may play b18 and make a ko out of the whole corner. RIGHT]))
(;B[ga];W[hb];B[da];W[fa];B[bc])))
(;W[ab];B[gb]C[Try to use the aji of d18!])
(;W[gb];B[fb];W[hb]C[B will happily give you the h19 stone... you could have done much more damage....])
(;W[bb];B[gb];W[ca];B[da]C[W can make much better use of d18...])
(;W[ge];B[gb])
(;W[ga];B[gb]
(;W[fa];B[hb];W[ea];B[fb]C[W fails.])
(;W[hb];B[fa];W[ha]C[A small reduction in gote. Much more is possible.])
(;W[ea];B[fb];W[hb]C[Even if W wins the ko, the reduction is not as big as possible.]))
(;W[gd];B[gb]C[Much more is possible.]))