Re: [gnugo-devel] New owl attack pattern

[Evan Berggren Daniel]

On Tue, 9 Sep 2003, SP LEE wrote:

> > you might even make that
> >
> > ; (lib(A) == 3 || lib(B) == 2 || oplay_attack(*,d,B) && proper_eye(c)
> >
> > since it seems entirely possible that shortening the liberty could
> change
> > the tactical status if there is a tactical semeai involved.  I don't
> know
> > if it would be worth the time to check or not though.
> >
> > Evan
> >
>
> I don't quite understand this constraint. Can you give an example? That
> is, lib (A) > 3 AND lib (B) > 2 and * is still a good move. Thanks.
>
> SP Lee

Sure:

O to play.

OOOOOO.
O....O.
OXXXXO.
OX..XO.
OXOOXO.
OOXXOOO
O.X.X.O
OOX*XOO
OOOX.O.
OOOOOO.

A bit contrived, but it works.  There is a tactical semeai above for the
life of the group, and winning it is insufficient to get two eyes.
However, if O throws in at *, then it costs O a liberty to keep the eye,
and the group dies.  Like I said, it seems kinda rare.

Evan Daniel