World Draughts Forum

It's been a while since I updated kingsrow for English checkers, but I recently posted a news item at the kingrow home page that I will paste here:

9/28/2026: I have built a 12-piece endgame db for English checkers. It's big! And it's available for download. More info here: https://edgilbert.org ...

Joost (and Gijsbert might also find this useful), I was looking through some of my draughts doc files and discovered that I had created a stats file with all the counts for the 2 through 7 pieces DTW db. Joost, I'm sorry that I didn't respond earlier when you were asking for DTW counts. I had ...

Thanks for the reply Ed. Can you tell me how much space a 10 figure database would take in GB? Of course, in draughts 10x10.

I have not worked out the details for 10 pieces. Building that requires more computing hardware than is available to the typical draughts programmer. AFAIK no one has yet ...

Krzysztof, in my tests kingsrow performed the same with either db in engine matches, and in test positions of 12 to 16 pieces measuring search time to obtain an egdb win or loss score. However version 1 is 389 GB vs 56 GB for version 2, so version 2 is much easier to manage on your internal drive ...

Ed, I heard from Bert that he doesn’t include positions with a 'non-side' capture in his database either. However, I’ve decided to include them because Ares frequently encounters positions where a 'non-side' capture needs to be evaluated. On a modern PC, it matters very little whether a database ...

Joost, as you may know, there are 2 versions of the kingsrow egdb. In version 1, I only exclude direct captures. In version 2, in addition to direct captures, for positions of 7 or more pieces that have more than 1 king present, I also exclude non-side captures (would-be captures if the side-to-move ...

Joost, I have this list of WLD counts for 2 through 7 pieces in my db. IIRC the counts exclude direct captures.

Notation: bBwW
0101b: wins 16, draws 2024, losses 2
0101w: wins 16, draws 2024, losses 2
0110b: wins 1516, draws 281, losses 0
0110w: wins 1, draws 574, losses 1510
1010b: wins 616, draws ...

I never understood the weird time-control with a fixed time and a fixed number of moves which often produces unknown results. Fisher time-control with increment is the only way to go. Joost, I agree completely.

Kingsrow does not clear the hashtable between games. If you use an aging mechanism then ...

Especially the last position, with the black king on square 4, a network will struggle greatly with this.
Yes, I think all engines will struggle with this. Kingsrow has no positional eval for kings at all, only material. Even the old HCE had nothing to deal with it.
Perhaps the networks learn that ...

Joost Buijs wrote: Thu Jul 23, 2026 17:09 This is a nice story about vibe coding: https://brandonharris.io/Garbage-Pail-Code/

Thanks Joost, that was very entertaining!

Here is one more:

lopsided7.png
[FEN "W:W31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50:B1,2,3,K4,5,6,7,8,9,10,11,12,13,14,15,17,18,19"]
It may not be clear from the image, but there is a black king on 4.

16 wins, 12 losses, 10 draws, 2 unknowns
All but 1 of the wins were black wins.

There has been a lot of discussion on this board about the problem that the strong engines always draw when they play another strong engine in a tournament. A few months ago I ran some experiments to see if this problem could be addressed using somewhat lopsided start positions. Below is a summary ...

CheckersGuy wrote: Mon Jul 06, 2026 18:10 The dll was probably not part of the checkerboard implementation in the past, right ?

Yes. Cake is part of the CheckerBoard install, and in 2021 Martin started using the egdb dll, so it was added to the CB install. Of course it was always part of the kingsrow install.

Bert, the egdb dll is included as part of the CheckerBoard installation, so it's not really necessary to have it in an engine distribution.

Robin, congrats on DarkHorse, it sounds like it is very strong, and I am looking forward to trying it. My computer has been tied up recently building more databases, but it will be finished soon and then I can start doing some of the other projects that I have been postponing.
Thanks for sharing ...