BQM566

Joseki from the book (dia. 1)  

This joseki is available at SL as 3-4, 5-3 enclosure, capping reduction

My variation (dia. 2)  

I played variations on a goban, and this is what kept me awake late

Only reasonable continuation for white I could find was at a.

Any thoughts?

Pekka23

Black split (dia. 3)  

I think Black has no good answer after , , . If saves the two stones, then makes Black a split shape.

Black corner gone (dia. 4)  

If cuts, then Black's corner is gone after . (Black can continue at a, but this would be a two-stage ko that favours White and heavy for Black.)

Black makes both extensions work? (dia. 5)  

Although the black shape is split, I don't feel it's bad. As far as I can read, white gets only a couple of kikashi to make black lose the corner, but white gets only one eye. The only option for white after this is to run into the center from a tight position. Is stealing the corner worth it, even if white does live?
As for diagram 4, I really don't like the way it looks for black.

And as for diagram 2, I really don't for the continuation, but it feels like my kind of move. :)

Pekka23

Slarty: The above is locally a success for white/bad for black, for being split. That kind of result is still dangerous for white though, it's true. Splitting directly with below is much easier, imo.

White unleashes her original threat  

symplicity: When evaluating the result, also remember that black started with 4 stones here. What would you expect if you took an typical even corner exchange and then gave black four moves in a row? Often it would be worse for white than dia 5.