Re: [gnugo-devel] Bug: gnugo plays inside own territory for no reason

[Gunnar Farnebäck]

SP Lee wrote:
> I do believe that N5 decreases white territory by 1 point in Japanese
> rule. Although it is seki in lower right corner, the white group has 3
> points and the black group has 1 point.

You are wrong. It's a basic premise of Japanese rules that no
territory is counted in seki and neither can you get points for "dead"
stones inside a seki if they remain on the board at the end of the
game.

> We could also imagine that the white group has a larger eye and
> captured 2 black stones and it is still seki. For example,
> 
>  8 . O . O X O X X . . X X X 8
>  7 O O . O O O X . X + X O O 7
>  6 X X O O O O O X . O X O . 6
>  5 X X O . X X O X X O X O X 5     WHITE (O) has captured 5 stones
>  4 X O O X X O O O O X X O X 4     BLACK (X) has captured 4 stones
>  3 X X X X . X O X X O O O O 3
>  2 . . O O X . X . X X O . X 2
>  1 . . . . X X X X X O O X . 1
>    A B C D E F G H J K L M N
> 
> However, now playing inside own territory will not decrease any point because 
> black has to throw in again to keep it seki.

It's indeed a seki but you are wrong about the scoring. White should
capture the two black stones, let black throw in, and capture that
stone too before passing, gaining three prisoners and thus three
points.

/Gunnar