|Original author(s)||Michael Byrne, Dr. Robert Hyatt, Tracy Riegle, Peter Skinner, Ted Langreck|
Crafty is a chess program written by Michael Byrne, UAB professor Dr. Robert Hyatt, Tracy Riegle, Peter Skinner and Ted Langreck. It is directly derived from Cray Blitz, winner of the 1983 and 1986 World Computer Chess Championships.
Crafty finished in second place in the 2010 Fifth Annual ACCA Americas' Computer Chess Championships. Crafty lost only one game to the first place winner Thinker.
Crafty also finished in second place in the 2010 World Computer Rapid Chess Championships. Crafty won seven out of nine games, finishing just behind the first place winner Rybka by only ½ point.
In the World Computer Chess Championships 2004, running on slightly faster hardware than all other programs, Crafty took fourth place with the same number of points as the third place finisher, Fritz 8. On the November 2007 SSDF ratings list, Crafty was 34th with an estimated Elo rating of 2608.
Crafty is written in ANSI C with assembly language routines available on some CPUs, and is very portable. The source code is available, but the software is for "personal use" only and redistribution is only allowed under certain conditions.
Crafty pioneered the use of rotated bitboard data structures to represent the chess board, and was one of the first chess programs to support multiple processors. It also includes negascout search, the killer move heuristic, static exchange evaluation, quiescence search, alpha-beta pruning, a transposition table, a refutation table, an evaluation cache, selective extensions, recursive null-move search, and many other features (cf manual). Special editions of the program include enhanced features such as an opening book, positional learning, and an endgame tablebase.
Vafra for Microsoft Windows is a free (by Robert Jurjevic cloned from Crafty) Winboard closed-source (similar to open-source Crafty) chess engine (bitboards, negascout parallel multithreaded brute-force alpha-beta search, transposition tables, move ordering, late move reductions, forward futility pruning, search extensions, quiescence search, evaluation function, endgame tablebases, opening book) with classical approach to chess.
Vafra chess engine can be used with ChessBase's Microsoft Windows Fritz chess interface (via Wb2Uci adaptor written by Odd Gunnar Malin) as an UCI chess engine to assist in chess analysis (Vafra chess engine chess playing style can be tailored by customizing chess position evaluation and chess graph search parameters stored in Vafra chess engine personality files).
- "Crafty Chess". craftychess.com. Retrieved 2010-08-18.
- "Crafty license with full author list". 2010. Retrieved 2013-04-21.
- "The SSDF Rating List". Swedish Chess Computer Association. 2007-11-03. Retrieved 2008-05-05.
- "186.crafty: SPEC CPU2000 Benchmark Description". spec.org. Standard Performance Evaluation Corporation. Retrieved 2010-05-11.
- Robert Hyatt. Retrieved on 1 May 2013.
- Chess Programming Wiki. Retrieved on 1 May 2013.
- Vafra. Retrieved on 1 May 2013.