opening book?

An abstract strategy board game for two players
Post Reply
flok
Posts: 12
Joined: Sat Jan 02, 2016 9:04 pm
Contact:

opening book?

Post by flok » Wed Nov 03, 2021 9:27 pm

Does Go have something like an opening book?
In what format is it?

If not: is there a standard way of hashing a Go board? (independent of the dimensions?)
www.ataxx.org / www.vanheusden.com

Rémi Coulom
Posts: 145
Joined: Tue Feb 12, 2008 8:31 pm
Contact:

Re: opening book?

Post by Rémi Coulom » Wed Nov 03, 2021 9:51 pm

The only standardised format for Go is SGF.

I am not aware of a standard way of hashing a Go board.

Here is the 9x9 opening book I computed with Crazy Stone:
https://www.crazy-sensei.com/book/go_9x9/

It handles transpositions into symmetries or rotations of the board. For this I needed a hash code that produces the same value for all 8 transformations of the board.

Some people tried clever ways to make hash codes that are invariant with board transformation:
https://www.mail-archive.com/computer-g ... 17519.html

But it is not clear whether this actually works. What I do is I compute the 8 Zobrist hash codes, compute S = sum of all hash codes, and pick the hash code h_i that minimizes h_i + S. This + S trick is to ensure uniform distribution of codes. Maybe using S as the hash code would work as well.

flok
Posts: 12
Joined: Sat Jan 02, 2016 9:04 pm
Contact:

Re: opening book?

Post by flok » Thu Nov 25, 2021 2:27 pm

Would it make sense for my tournament software to start with a few randomly placed stones for both sides? In case neither of the players has a way of randomizing and would play the same game over and over again?
www.ataxx.org / www.vanheusden.com

Rémi Coulom
Posts: 145
Joined: Tue Feb 12, 2008 8:31 pm
Contact:

Re: opening book?

Post by Rémi Coulom » Thu Nov 25, 2021 2:36 pm

Starting from varied positions is important. Two games should be played from each starting position (swapping colors). If you maximize territory, then completely random positions are OK. Otherwise, if you maximize the probability of winning, then you should try to somehow select positions that are balanced.

Post Reply