In a game review some proposed that this white would kill the group. It's not easy to see that this is wrong.
Some variations are a bit complicated, hope i got everything right. Comments are more than welcome. thanks to tails, nutcase and LCZLAPINSKI for a comments
(;AB[fb]AB[gb]AB[gc]AB[hc]AB[kb]AB[kc]AB[ic]AB[lb]AW[mb]AW[lc]AW[md]AW[kd]AW[jd]AW[id]AW[hd]AW[fc]AW[gd]AW[eb]AW[ec]AW[cb]AW[fd]AW[ha]C[Black to live]AP[goproblems]
(;B[ia];W[ib]
(;B[ja];W[jb]
(;B[jc];W[ka]
(;B[la];W[fa]
(;B[ja]
(;W[ia];B[ga];W[ka]
(;B[ea];W[ma]
(;B[ja]C[Alright, white cannot win both kos ! RIGHT])
(;B[hb];W[fa]))
(;B[ja]C[NOTTHIS]))
(;W[ga];B[hb]C[RIGHT]))
(;B[ga];W[ja];B[ea];W[ma])
(;B[hb];W[ia]
(;B[ga];W[ma])
(;B[ja]C[Two step Ko for white. Black can do better !])))
(;B[fa];W[la];B[ja];W[ma])
(;B[ia];W[la];B[hb];W[ja])
(;B[ja];W[ia];B[la];W[fa];B[ga];W[ma]
(;B[ja]C[Alright, you did see that you live by creating another ko at E19 later and white can't win both, right ?RIGHT])
(;B[ea];W[da];B[ja]C[Nice, white can't win both of the ko's so black is alive with territory.RIGHT]))
(;B[hb];W[la];B[ja];W[ia];B[ga];W[fa]))
(;B[ka];W[jc])
(;B[hb];W[jc])
(;B[fa];W[jc])
(;B[ga];W[jc]))
(;B[jc];W[ja]
(;B[fa];W[la];B[ka];W[hb]
(;B[jb];W[ia])
(;B[ga];W[ia]))
(;B[la];W[fa];B[ga];W[jb]
(;B[hb];W[ia])
(;B[ka];W[ia])))
(;B[jb];W[ja])
(;B[hb];W[ja])
(;B[la];W[ja])
(;B[fa];W[ja]))
(;B[jc];W[fa]
(;B[ga];W[ib]
(;B[hb];W[ia]
(;B[ja];W[la])
(;B[la];W[ja]))
(;B[ia];W[ja])
(;B[ja];W[la]
(;B[hb];W[ia])
(;B[ia];W[hb]))
(;B[la];W[ja])
(;B[jb];W[ia]))
(;B[ia];W[ib]
(;B[ja];W[hb]
(;B[la];W[ga])
(;B[ga];W[la]))
(;B[ga];W[ja])
(;B[jb];W[ja])
(;B[hb];W[ja])
(;B[la];W[ja];B[ga];W[jb]
(;B[hb];W[ia])
(;B[ka];W[ia])))
(;B[ib];W[ga];B[ja];W[la])
(;B[ja];W[la];B[ga];W[ib]
(;B[hb];W[ia])
(;B[ia];W[hb]))
(;B[la];W[ga];B[ja];W[ib]))
(;B[la];W[jc]
(;B[jb];W[fa]
(;B[ja];W[ga])
(;B[ga];W[ib];B[ea];W[ja]))
(;B[ia];W[jb])
(;B[fa];W[jb])
(;B[ib];W[jb]))
(;B[ja];W[la];B[jc];W[fa]
(;B[ib];W[ga])
(;B[ga];W[ib]
(;B[hb];W[ia])
(;B[ia];W[hb])))
(;B[fa];W[jc]
(;B[la];W[jb])
(;B[ib];W[jb])
(;B[ja];W[jb])
(;B[ia];W[jb])
(;B[jb];W[ia]
(;B[ja];W[la])
(;B[ib];W[la])
(;B[la];W[ib]
(;B[hb];W[ja])
(;B[ja];W[ma]))))
(;B[jb];W[ib]
(;B[hb];W[ia])
(;B[la];W[ja])
(;B[ja];W[la])
(;B[fa]C[Black is still dead.])
(;B[ga];W[ja]))
(;B[ib];W[jc]
(;B[jb];W[la]
(;B[ka];W[ia])
(;B[fa];W[ka])
(;B[ia];W[ka]))
(;B[ia];W[jb]))
(;B[ka];W[jc]
(;B[ib];W[jb])
(;B[jb];W[ia]))
(;B[ga];W[jc]
(;B[ib];W[jb])
(;B[jb];W[ib])))
tom111