Re: computer-go: Is this a legal move?

["Andrew Derrick Balsa" <andrebalsa@xxxxxxxxxxxxxxxxxx>]

Hi Todd,

Yes, this position is legal, and like any other legal position, it can be
reached  by a combination of White or Black playing stones or passing.

In practice you should add at least one heuristic to your player,
preventing it from filling in its own single-stone eyes. This is not so
hard and you can base yourself on Randyplus, my random player, which can
optionally play random moves **with the exception of filling in its own
single-stone eyes**.

The other way to prevent a big loop is adding a Superko rule to your
player. This involves storing a ¨history¨ of past positions - the best
format is a linked list of hash codes (e.g. Zobrist keys) for the past
played positions. Not as easy as the other rule, but doable.

G'luck,

Andrew

On Sun, 2 Mar 2003 14:38:27 -0800, "Todd Detwiler"
<todd_detwiler@xxxxxxxxxxxxxxxxx> said:
> Sorry if this is an innapropriate message for this list, I am new here
> (and new to Go as well). I illustrate with a 5x5 board where W=white,
> B=black, and _=vacant intersection):
> 
> BBBBB
> BBB_B
> BBBBB
> BBBBB
> BBBBB
> 
> If it is white's turn to play and they play in the one remaining open
> intersection, do they remove all of the black stones from the board? It
> would, after all, remove the last remaining liberty of that group. I
> realize that this probably never happpens in human play, but I am working
> on a computer Go player and, when I play it against itself, the game
> never seems to end because it keeps encountering the aforementioned
> situation and basically clearing the board, with this play, and starting
> over.
> Thanks,
> Todd

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