|Developer(s)||Anthony Cozzie, Zach Wegner (since 2010)|
|Initial release||February 2, 2005|
|Stable release||Zappa Mexico II / 2009|
|Operating system||Microsoft Windows, Linux|
Zappa, Zap!Chess or Zappa Mexico, is a UCI chess engine written by Anthony Cozzie, a graduate student at the University of Illinois at Urbana-Champaign. The program emphasizes sound search and a good use of multiple processors. Earlier versions of Zappa are free (though not open-source software) and the current version (Zappa Mexico) is available at Shredder Computer Chess.
Zappa scored an upset victory at the World Computer Chess Championship in August, 2005, in Reykjavík, Iceland where it won with a score of 10½ out of 11, and beat both Junior and Shredder, programs that had won the championship many times. In the speed chess portion of the tournament Zappa placed second, after Shredder. Zappa's other tournament successes include winning CCT7 on the Internet Chess Club (ICC) and defeating Grandmaster Jaan Ehlvest 3-1.
In Mexico in September 2007 Zappa won a match against Rybka by a score of 5½ - 4½. Many commentators had predicted a slew of draws based on the strength of the engines, but the differences in style provided an interesting match with several decisive games and many fighting draws. For some time, Zappa was considered one of the two strongest commercially-available chess programs; see engine rating lists like CCRL for current rankings. Some speculate that Zappa's more efficient SMP parallel search could make it stronger on enough processors.
In March 2008 Anthony Cozzie announced that "the Zappa project is 100% finished", which includes both tournaments and future releases.
In June 2010, Zach Wegner announced that he had acquired the rights to maintain and improve the Zappa engine. The improved engine competed in the 2010 WCCC under the name Rondo, achieving second place behind Rybka before the latter's disqualification.
Immediately after the successful WCCC 2005, there were plans to commercialize Zappa, but the first attempts with Vincent Diepeveen failed. In April 2006, a commercial version dubbed Zap!Chess running under the Fritz GUI was released by ChessBase.
The version of Zappa that won the Zappa-Rybka match, Zappa Mexico, is sold by Shredder Computer Chess, is compatible with Windows and Linux computers with up to 512 CPU cores and supports multipv analysis and Nalimov tablebases.
- Zappa vs Crafty, WCCC 2005, 1-0 Despite Zappa being a relative newcomer, it managed to win the tournament and in general caused a bit of a stir in the computer chess community.
- "Zappa Mexico". Retrieved 26 October 2013.
- "13th World Computer Chess Championship". IGCA. Retrieved 26 October 2013.
- Cozzie, Anthony. "WCCC 2005 Photojournal". Archived from the original on 22 March 2012. Retrieved 26 October 2013.
- "WCCC 2005 Reykjavik". rpijl.home.xs4all.nl/. Archived from the original on 25 October 2013. Retrieved 26 October 2013.
- "Shredder". IGCA. Retrieved 26 October 2013.
- "Junior". IGCA. Retrieved 26 October 2013.
- "13th World Computer Chess Championship (Blitz)". IGCA. Retrieved 26 October 2013.
- "CCT Results". Retrieved 26 October 2013.
- "Report". Retrieved 26 October 2013.
- Cozzie, Anthony. "Match vs Rybka - Mexico 2007". Retrieved 26 October 2013.
- CCRL engine ratings: http://computerchess.org.uk/ccrl/4040/
- "Anthony Cozzie". Netfiles.uiuc.edu. Retrieved 2012-06-20.
- Rybka placed first but the program was found to have plagiarized Crafty and Fruit(the GPL'ed runner-up in 2005), and was stripped of its title. (Doggers, Peter. "Rybka disqualified and banned from World Computer Chess Championships". Chess Vibes. Retrieved 29 June 2011.)
- "Zach, is this true?". Retrieved 26 October 2013.
- "Zappa". ICGA.
- Cozzie, Anthony. "Re: Zappa Retail: No UCI?". Retrieved 26 October 2013.
- "World Computer Chess Champion: Zap!Chess". ChessBase. Retrieved 26 October 2013.
- "Zap!Chess". ChessBase. Retrieved 26 October 2013.
- Cozzie, Anthony. "Great moves". Retrieved 27 October 2013.
- "Zappa official website". Archived from the original on 18 September 2012. Retrieved 26 October 2013.
- Newborn, Monty (2011). Beyond Deep Blue: Chess in the Stratosphere. Springer. ISBN 978-0-85729-341-1. Retrieved 26 October 2013.