KingsRow is a free checkers engine for CheckerBoard written by Ed Gilbert.
KingsRow
for English checkers
KingsRow
for Italian checkers
Obtaining the 10-piece db for English checkers
Book10, an auxiliary opening book for English
checkers.
5x5 endgame animations from the MTC database
Endgame database drivers (for checkers
programmers)
7/1/2009: A new version of KingsRow for English and Italian checkers is now available, and also a new version of CheckerBoard. KingsRow now has a parallel search engine, which can give up to a 3x speedup with multi-core CPUs. Details of the changes are given here, and setup files can be downloaded at the English and Italian checkers links above.
8/30/2008: I have added an expansion of Wyllie's famed "Invincible" to the 10-piece book. Details and opening book file download here.
12/5/2007: A new version of Kingsrow which plays 10x10 international draughts won a tournament in the Netherlands against 9 European programs. You can read about it here.
7/7/2007: I have updated the install file for Italian Kingsrow. The Kingsrow program is unchanged, but the opening book has been increased to 725,000 positions.
5/22/2007: The 10-piece db for English checkers is now available! See details here. There are also new versions of KingsRow (1.16c) for both English and Italian checkers with engine and opening book improvements.
12/5/2005: 9-piece and partial 10-piece Italian databases are coming. In October I finished building the 5x4 subset of the 9-piece Italian database. I also built some of the most useful parts of the 10-piece Italian db -- 5x5 positions with one king or less on a side. Normally this requires computing all the positions with more kings also, a process that took me nearly a full year using 4 computers for English checkers. But I computed these 10-piece positions in about 3 weeks by skipping the more king-heavy positions. There is a disadvantage to doing it this way -- some of these positions rely on the missing positions with more kings, and therefore cannot be resolved. However it turns out that only a small percentage of the positions cannot be resolved, so this was a nice way to make the Italian KingsRow more powerful with only a small additional computing effort. Here is a table which shows the percentage of positions that are resolved in each 10-piece slice.
I have been building a new opening book using these databases. When I first built an opening book for Italian checkers using an 8-piece db, I discovered that 9 of the opening ballots are probably forced losses for the weak side. Using the new larger databases I have found 2 more ballots that are probably lost. These are 21-18 12-15 22-19 and 23-20 12-15 22-19. The new opening book and endgame databases will be available in early 2006.
7/17/2005: The 10-piece database is finished. Read the story of how it was built.
1/12/2005: 10-piece database progress. In August I started computing the 10-piece endgame database. It is being built by a cluster of 4 PCs. At the current rate of progress it will be completed this summer, and it will occupy 150GB of disk space. About 42% of the database has been built, and most of this data has been verified against Jonathan Schaeffer's database. I am also saving the 'moves-to-conversion' data, which is generated with almost no additional effort as a byproduct of computing the win-loss-draw data. The MTC data is useful for solving very difficult positions that require a large number of moves before a conversion move occurs. More information about the MTC data along with some of these most difficult 10-piece endings and the moves to play them correctly is here.
11/28/2004: Cake wins the long CheckerBoard engine match! Cake won a 624-game computer checkers match against KingsRow by a score of +3 -1 = 620. The match games can be downloaded here. Details of the match announcement are here.
2/12/2004: Attention checkers programmers: I am making available the endgame database drivers that are used in KingsRow. These drivers, which are provided in the form of a .dll file, provide high-performance access to the Cake, Chinook, and KingsRow English and Italian databases. Documentation on the API is in the header file. Download here. (Note: these drivers are only useful to people that are writing checkers programs. If you are only using a checkers program you don't need this package.)