Rémi Coulom wrote:
Yes. The recipe is:
- play as usual with Chinese rules,
- take a one-point security margin with respect to komi,
- pass as soon as the opponent passes.
You also have to be careful to score seki the Japanese way in the
playouts. This is the most difficult part. If your playouts don't
understand seki, then you can just ignore seki, or take more than one
point of security margin if you wish to be safe.
I don't think that works even if there is no seki, because what happens
if your opponent passes in a position in which there are still unsettled
groups? If you blindly pass after the opponent's pass and thereby
terminate the game, who will own the unsettled group under Japanese rules?
Here is what Fuego does:
Fuego uses Tromp-Taylor rules internally, which makes scoring of
terminal positions after two passes trivial. If the value of the root
node is very close to a win after half of the search resources are used
(time or node limit), the search aborts early. Then a second search is
started that checks if the position is still a win after the player to
move plays a pass. If this is so, and the point ownership statistics
show that the status of all points is decided (close to 0% or 100%) then
the player passes, even if the best move of the first search was not a pass.
The original idea for this was to pass as soon as a position is won and
the status of all points is decided, because continuation of play in
this situation offends some humans. But as a side effect, it also avoids
to lose points if the game is played by Japanese rules. We haven't done
anything for dealing with the different scoring of seki in Japanese
rules yet.
In reality, the algorithm is a bit more complicated, because there could
also be neutral points and Fuego tries to detect them and play moves to
fill them. In fact, under some circumstances there are three searches
necessary. You can find all details in GoUctPlayer::DoEarlyPassSearch()
in Fuego's source code.
- Markus
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