No idea where this links from - got here via the Random Page button. My rank beginner eye tells me:
IainK?: Kills? If Black plays a or b then White kills the bottom left group with the other. If Black plays c then White b kills the left 6 stones. If Black plays d then White plays b; after which if Black connects at a he leaves the bottom-left group in atari, but if he lets the stone above a be captured he loses the ability to make a second eye.
fractic: I think you are on the right track but after black d white b it's not as easy as you make it look.
fractic: sets up a snapback against the two white stones. But white cleverly counters with her own snapback threat at .
fractic: Black has no other choic then to go along like this but this leaves the eye at false. A similar play is needed when black starts with c instead of d.
FireclawDrake: a and b are now miai for kill.
Reuven: Have you considered this? I think the marked locations are miai.
Reuven: It seems better than the following variation though as W takes first here.
Reuven: Since this fails for B,
Reuven: At this point it has to be some kind of a ko of course, but how would you go about it? Does -, b taking first satisfy you?