H3 is why. If white plays B4, black can threaten to connect underneath and live locally. If white plays D2 and pulls back to E2 to shrink black's eyespace, after black attaches at B5 there's a weakness white has to protect outside, letting black make two eyes (or take the eye point and watch black destroy white's moyo by running.)fwiffo wrote:I'd like to discuss what happened in the lower left in the final. Specifically, how was it possible that a 3-3 invasion of that enclosure could live?
Black's not unconditionally alive yet - white F2 is sente against a ko in the corner.
and 
are quite popular lately, but the sequence 
- 
that follows is not one I recall seeing before, and I didn't find it in a database search (based on last summer's GoGoD). Is it a new joseki? I'd like to hear some stronger players' comments.
does not appear. It looks funky to me but I am not Lee Changho. I suppose black answers with a stone on the 2nd line, so maybe that makes up for it.