BQM 344
xela: These are the first two problems in the second part of 200 Tesuji Problems. In both cases it is black to play and invade the corner.
The book gives a variation for at
; of course there are many other variations possible, but my understanding is that the author is asserting that black can live unconditionally no matter what.
Now for problem 1, white's corner is more open, so I would expect that black would be able to do even better than in problem 2. This is what the book says:
(There is a variation diagram saying that at a, trying to kill the black stones, is unreasonable.)
Taken on its own this looks like a reasonable result; but comparing it to problem 2, I don't understand why black wouldn't play at
to live without ko.
MrTenuki: According to the butterfly page, Black can even invade at 3-3 and live unconditionally in this case...
Dieter: some first thoughts, without much analysis