Re: computer-go: 5x5 Go is solved?

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

Jean-Pierre Vesinet wrote:
> I don't understand your GHI problem with superko. Either you have basic ko +
> long cycle no result (as in Japanese ko rules) or superko. You cannot have
> both at the same time.

The problem is not that I don't understand the rules. The problem is
that I don't want to check the future of each position stored in the
transposition table with the history of the current position where a
transposition (TT) is found. 

Think of the following line:
A-B-...-C-...-B-...

since B is illegal because of superko this will become:
A-B-...-C-...-D-...

C is stored in the TT 

Now after some time we search:
E-F-...-C-...

C is found in the TT so this line will not be expanded further.

However the value of C is based on the continuation C-...-D where
C-...-B-... may give a higher score (unless somebody could prove to me
that this cannot exist in real Go).

I hope this clarifies the problem.

> 
> You could try solving some problems from the Super Book of 5x5 Go by Fukui
> Masaaki for testing purposes. There are 3 at
> http://www.msoworld.com/mindzine/news/orient/go/special/cameos/cameo7.html.

Nice problems. I tested the examples. My search solves all three in less
then two minutes.


> You could make a problem generator and publish a book of solved problems.
> Some very nice problems exist even on a board as small as 5x5. The problem
> is to capture the essence of what a nice problem is. The criteria could be
> something like:
> - small branching factor in the solution (only a few variations work,
> everything else fails),
> - unexpected solution (contradicts what heuristics expect).

Nice idea, unfortunately I don't have the time to do this in the near
future.

Regards,
Erik