Re: [gnugo-devel] tsumego Evan Berggren Daniel

[SP LEE]

>
> However, there are some known problems that are particularly
highlighted
> by this problem set, mostly related to strange shapes (under the
stones
> shapes are unlike most others; you'll find that people who haven't
looked
> at the problems are particularly bad at them as well, I think).  The
other
> major problem is cutting points in eyespaces, like in the position you
> posted.  The first can be solved by the addition of patterns or some
more
> sophisticated technique, the second probably requires major work on
the
> owl code.  The third problem also relates to eye valuation, as in the
> following position (from problem #1):
>
> |OOO
> |XXO
> |XXO
> |.OX
> +---
>
> How many eyes is this for white?  Gnugo currently believes it is one
eye.
> This is clearly wrong, but the position is more subtle than
immediately
> obvious, because if black is asked to prove it, then he has to capture
> from the outside first, otherwise white can get a ko (black takes the
> stone, white takes the black stones):
>
> |OOO
> |..O
> |21O
> |.OX
> +---
>
> Now white has a ko for two eyes.
>
> Actually, this is probably equivalent to the cutting points problem in
> many ways, but is probably different enough to be worth considering.
>
> Evan Daniel
>

I hope my following comment is not irritating. If black plays at '2'
instead of '1', it is still one eye for white.


SP Lee