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

[stefanmertin@xxxxxxxxxxx (Stefan Mertin)]

Erik van der Werf schrieb:
> Yesterday my program solved 5x5 Go starting with the first move in the
> centre. As was expected it is a win for the first player with 25 points
> (the whole board belongs to black).
>
> I used an iterative deepening Alpha-beta search (PVS) with:
> - Transposition tables (2-deep replacement scheme, 2 x 2^24 entries)
> - Enhanced transposition cut-offs
> - Symmetry lookups in the Transposition table
> - 2 killer moves
> - History heuristic
> - Benson's algorithm for unconditional live (extended with unconditional
> territory)
> - Heuristic evaluation for positions that are not fixed by benson
>
> The solution was found at 22 ply deep (23 for the empty
> board).(searching 4.472.000.000 nodes in about 4 hours on a P4 2.0Ghz)


Congratulations!

But...

I don´t know if I really understood everything well but
a program that shows me a way to win from only one position 
(empty board where Black may play in the centre) 
is not what I was looking for...

Perhaps I am too much player (of modest strength) and
not enough mathematician, but aren´t there lots of 
very interesting possible positions in 5x5 Go that 
your program doesn´t cover...?

I think e.g. of all the very fine 5x5 ploblems in "GoWorld"
or of all the perhaps even more interesting games, were 
black is not allowed to put his first move in the centre!

What I really would enjoy is a program that tells me in 
(nearly) ANY position something about EVERY move - 
at least if it is a winning or a loosing line or jigo.

More I think about it, more I am convinced, that something like this
should already be possible for 5x5 Go with todays hardware-possibilities
and that it would be a very funny thing for every Go player to
"surf around" in such a database.

I admit that a pure database solution will no more be practicable
for larger boardsizes and thus your searching way may be more
useful for the progress in computer Go - but perhaps it could even be
possible to find some new improvements for searching algorithms in 
comparing their results in 5x5 Go with the perfect play of my 
proposed database. 

In any case it should be a great thing to show to the "public":
everyone would finely admit, that computer Go on a 19x19 board must
be extremly hard to realize !!!  :-)

I really think DON`T UNDERESTIMATE 5x5 GO !

( 5 in Japanese is "go" !)


Stefan