[gnugo-devel] Tripod group

[bump]

I'm wondering if ld_owl:151 is correct.

Here's the position.

+-----------
|..*........
|...X.......
|.XXOOOOO...
|..OO.......
|..O........
|..O........
|..O........

Surprising, but it seems to me that an attack by O at C19
can produce at least a ko.

I have in front of me a volume of Tsume Go problems by Cho
Chikun (Chinese edition, I think) who considers a very
similar position on p.98 and does not consider the move at
C19.  However I cannot find a refutation better than
ko. For a while I thought that pushing along the side at
E18 worked, but GNU came up with B19 leading to this position:

+-----------
|.OO........
|...XX......
|.XXOOOOO...
|..OO.......
|..O........
|..O........
|..O........

I can't find anything better than ko for black.

Am I missing something?

Dan