Herman Hiddema: Have you considered at a? It's an interesting variation...
Imagist: You're right! I was filling in this solution from memory and I forgot about that variation! I've added it below.
The order of and is unimportant. or at both threaten a followup at which creates a small capturing race that catches the - stones. is the only way to prevent this.
(or at ) is a tesuji that threatens to make a second eye and also reduces the liberties of the resulting - - group. This allows black to respond to with .
The order of and is not important.
Herman Hiddema: White should play (instead of a), then after , , Black lives in gote by playing at . This way Black does not get an endgame capture.
Imagist: Black to lives with only two points territory and three captured stones, and in gote. This leaves a small endgame play at a for either player.
Imagist: Even better would be for white to connect in sente instead of trying to play nakade. :)
Bill: I kind of like this one. Not that it is correct play. ;-)
Imagist: Allowing is difficult to justify, but if white is strong in the area the points gained by creating a seki might make up for it.