This is not the kind of problem you can solve on the back of a beer mat. After , Black has the problem of whether or not to directly block the diamond life in the corner. After
I imagine
is forced, which lets White obtain A, a move which is sente against the corner. Of course,
and
are not forced.
So I come to next to this position. So far I assumed and
are interchangeable. Here Black needs to consider b or a. Given the outside, I assumed that Black can clearly play the former with ko, but then he must logically prefer the latter if it allows him the chance to kill..