Building the Checkers 10-piece Endgame Databases

In 1993, the CHINOOK team completed the computation of the 2 through 8-piece checkers endgame databases, consisting of roughly 444 billion positions. Until recently, nobody had attempted to extend this work. In November 2001, we began an effort to compute the 9- and 10-piece databases. By June 2003, the entire 9-piece database and the 5-piece versus 5-piece portion of the 10-piece database were completed. The result is a 13 trillion position database, compressed into 148 GB of data organized for real-time decompression. This represents the largest endgame database initiative yet attempted. The results obtained from these computations are being used to aid an attempt to weakly solve the game. This paper describes our experiences working on building large endgame databases.