Kingsrow for English/American checkers

Kingsrow is a checkers engine which is designed to be used with Martin Fierz's user interface program called CheckerBoard. Both Kingsrow and CheckerBoard are free programs and can be downloaded using the links below. 


The CheckerBoard install files below are more current than the ones at Martin's site. They have new bug fixes, enhancements for PDN3.0, and the PDN search function now works with all the different checkers variations supported by the program.

For programmers, the CheckerBoard source code is available at GitHub.

Opening Book 

Kingsrow has an opening book database of 1.4M positions. It covers all 174 of the 3-move openings. The book was built by doing systematic searches with Kingsrow. This technique is called dropout expansion and was developed by Thomas Linke. It is described in his paper "Exploring the Computational Limits of Large Exhaustive Search Problems". Martin Fierz has written an overview of how dropout expansion works.

As of July 2016, most of the opening book was re-generated using the 10-piece db and a much faster computer than when the book was originally built more than 10 years ago. I also had been maintaining a separate opening book file I called 'book10' with analysis of some difficult positions. The book10 data has been merged into the standard book file.

Endgame Databases

New as of July 2016, I have re-compressed the 10-piece database, using better compression techniques that result in smaller files. The files are now small enough that they can be downloaded from a file server. Previously the WLD files required 214gb of hard drive space, and I had distributed them on an external USB drive. They are now 102gb. If you have the older format db you can continue to use it. There is some advantage to using the newer db because it makes better use of your cache memory.

Kingsrow can also use the 8-piece WLD databases available from Jonathan Schaeffer (Chinook website) and Martin Fierz (CheckerBoard website). During engine setup you will set the path to the directory where the endgame database files are located. Kingsrow automatically detects the type and size of the database that is present.

You can download install files for the 10-piece endgame databases using the links below. To use the 9 and 10-piece databases, you also need to install the databases of 2 through 8 pieces. The files are hosted at Mega. For downloading these large files, Mega only supports Chrome and Opera web browsers. More about downloading from Mega.

Each install contains a group of .bin files and an .exe setup program file. Download all the files to your PC, then run the setup program to install the database on your hard drive.

If you have the earlier version of the endgame databases, either delete those files first, or install these files in a different directory. Kingsrow will work with either version of the databases, but the older version files take up a lot of space on your hard drive, and there is no reason to keep them if you have the new databases. After you install the new databases, you should tell kingsrow where you put them. Use the Checkerboard menu Engine, Options, More Options, and use the Browse... button under WLD database to enter the directory path to the db files. There is more information in the help file (menu Engine, Help).

Ed Gilbert
Last revised: October 12, 2018.