unkx80: This position came about from a joseki variant of 3-4 point low approach two-space high pincer two space jump where White is said to have overplayed, see /Background for more.
The BQM here is: how should Black play if descends instead of playing at a? This question was originally brought up for http://GoProblems.com problem 8190. Thanks.
AJP: some playing around seems to show that up to black wins the capturing race.
Alex: Really? Up to , it seems like a pretty clear-cut case of 4 liberties vs. 3. Can Black win by making an eye if he plays at ?
Bill: How's this?
Then a solution that appears to preserve the key stones would be a ko, I suppose.
Bill: Well, losing the corner in a 5 vs. 5 semeai, where White has to actually capture all of Black's stones (semedori), would normally be a good result in the opening. Is sacrificing the corner in semedori better than allowing ?