Re: [computer-go] GTP and Tourney in SmartGo 1.4

[Erik van der Werf <E.vanderWerf@xxxxxxxxxxxxx>]

David Fotland wrote:
> > In any case, information about rule set can be passed via
> > command line.  And even if it is not, difference between chinese
> > and japanese scoring is so insignificant that it hardly will
> > influence playing style of any engine.
>
> Rules make a huge difference.  With Chinese rules there is no problem 
> with trying
> horrible invasions at the end of the game if you are behind, looking for 
> some bug in the
> opponent.  With Japanese rules, these moves will lose you a lot of 
> points.  Go4++
> used to do this.
Really???

Under normal circumstances the differences between Chinese and Japanese rules 
can be neglected during the game, i.e., a move which is bad under Japanese rules 
is nearly always equally bad under Chinese rules. At the end of the game the 
score is usually the same up to one point. Only when, at the end, one player is 
passing and the other is playing further this difference may grow because a pass 
gains a point under Japanese rules. However as long as moves are answered the 
difference remains equal.

Now what does this mean in practice for the following two scenarios:

1)  Program 1 (P1) is ahead and passes, Program 2 (P2) tries David's horrible 
invasions

Chinese: Playing the horrible invasions is free but P1 may respond also for free 
and most likely wins anyway. If P1 is not able to defend his territory he 
doesn't deserve to win anyway.

Japanese: Playing the horrible invasion costs points as long as P1 passes but P1 
does not have to do this since he's ahead anyway. Moreover since P2 is behind he 
might just as well start the horrible invasion, because he would loose anyway. 
Therefore in this situation Japanese rules do not prevent a program from trying 
the horrible invasions.


2)  Program 1 (P1) is behind and passes, Program 2 (P2) tries David's horrible 
invasions

Chinese: P1 looses anyway so he shouldn't complain (P1 can always resign if he 
doesn't like to play further)

Japanese: P1 would loose if P2 was smart enough to pass. However, P2 is stupid 
and plays on thereby loosing points and possibly even giving a win to P1. So 
this scenario would actually favor P1.


From the above it seems clear that the only case where the rules matter is in 
situation where the game is (close to) jigo which IMO does not justify the claim 
that this would make a huge difference.

Best,
Erik



PS Another problem, which I do not like to discuss here, is that it is next to 
impossible to correctly implement the official Japanese rules. For more info see 
the lengthy discussions about Japanese rules on rec.games.go



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