Re: [gnugo-devel] tiny boards

[Gunnar Farnebäck]

Dan wrote:
> Test tiny:209 is quite interesting.
> 
> The answer A2 leads to seki, but B can also try D2.  W can
> make a ko at A2 but B will have the first capture. In this
> case B kills everything.

Agreed, total collapse for white in this variation.

> However W can play C4 in answer to D2 which leads to 10,000 year ko:

   A B C D
 4 O X X X 4
 3 . O X . 3
 2 O O X X 2     WHITE (O) has captured 1 stones
 1 . O O . 1     BLACK (X) has captured 1 stones
   A B C D

> This becomes seki since neither player can fill the ko,

Not quite, it becomes seki since neither player can fill D1 and then
fight the ko. In this position black has to pass and then white fills
the ko. That gives W+1 under Chinese scoring (no komi) and jigo under
Japanese scoring (no points in seki and one capture each). The
variation in games/tiny/4x4a.sgf ends in a seki which is B+2 under
Chinese scoring and jigo under Japanese scoring.

> but if we consider the local game (hypothetically as a summand in a
> larger game involving several boards) it's not quite the same.

Yes, with ko threats on the board the ko can sometimes be fought.

/Gunnar