From Chessprogramming wiki
Jump to: navigation, search

Home * Engines * Zappa

an UCI compliant chess program developed by Anthony Cozzie. Zappa won the WCCC 2005 in Reykjavík, and after the Rybka disqualification in 2011 the WCCC 2007 in Amsterdam, the DOCCC 2005 and CCT7.During the World Chess Championship 2007 in Mexico City, September 2007, Zappa played a match versus Rybka and scored 5.5 / 10 to win the match [2] [3] [4] . Zappa's book authors for different events were Arturo Ochoa (CCT7) and Erdogan Günes [5] .




Anthony Cozzie before round 7, Zappa - Junior, WCCC 2005 [7]


Zappa Team, Anthony Cozzie and Erdogan Günes, Closing Dinner WCCC 2006, Turin


Zappa is not directly named for Frank Zappa, but from a scene from Austin Powers 2, where Dr. Evil's base in the moon is divided in two units: Moon Unit Alpha and Moon Unit Zappa - the latter being the name of Frank Zappa's daughter, Moon Unit Zappa [8] .

Strictly Commercial

Immediately after the successful WCCC 2005, there were plans to commercialize Zappa. First attempts with Vincent Diepeveen involved failed [9] . In April 2006 [10] , a commercial version dubbed Zap!Chess running under the Fritz GUI was released by ChessBase. The version which played the Rybka match, Zappa Mexico, is distributed by Stefan Meyer-Kahlen.

Quote from No Commercial Potential : The Saga of Frank Zappa (1972) by David Walley, p. 4 [11] [12] [13] :

Jawaka Information is not knowledge

Knowledge is not wisdom
Wisdom is not truth
Truth is not beauty
Beauty is not love
Love is not music
Music is the best

Program Internals

Board Representation

Zappa utilizes bitboards and uses rotated bitboards to generate sliding attacks on the fly. Anthony once experimented with incremental updated attack tables, which was a win on 32-bit systems [14] .

Hash Collisions

Excerpt from The Effect of Hash Signature Collisions in a Chess Program, that is Crafty and Zappa [15] :

Both programs are traditional computer chess programs that use the alpha/beta algorithm to search a minimax game tree. The search is done in three distinct phases.
Phase 1 is the normal full-width search that is done to some fixed depth as limited by the total time allowed for a move. This fixed-depth search is modified by various search extensions.
Phase 2 is an add-on search done after the basic search has reached a satisfactory depth. Phase 2 only considers captures in Crafty, while Zappa also includes some checking moves.
Phase 3 is the static evaluation, which takes the current position after phase 2 has completed, and computes a numerical score based on the material, the locations of the pieces, pawn structure, and many other positional considerations. In Crafty/Zappa, all of the hashing is done in phase1 of the search, there is no hashing in the quiescence search. 

Singular Extensions

Zap!Chess, the commercial ChessBase version, has an implementation of Singular Extensions, the famous Deep Blue search algorithm. They are disabled by default, but they increase the tactical strength of the program at the cost of positional strength [16] .

Parallel Search

Zappa was designed to run on multiple processors and massive parallel systems using shared memory and threads and has an efficient parallel search [17] . Zappa Mexico can be used on Windows or Linux computers with up to 512 CPU cores.

100% Finished

In March 2008 Anthony Cozzie announced that "the Zappa project is 100% finished", which includes both tournaments and future releases [18] .


In 2010, Zach Wegner started to work with Anthony Cozzie, who, still in computer chess retirement, has given control for further development of his massive parallel program, now called Rondo, to Zach [19] [20] .

See also


Chapter 9: 2005: Zappa Red Hot at 13th WCCC, page 119
Chapter 14: 2007: Zappa Upsets Rybka in Mexico City, 5.5–4.5, page 169

Forum Posts



2005 ...

Re: Zappa Report by Ingo Althöfer, CCC, December 30, 2005 [21]


  • Zappa? by James T. Walker, CCC, January 27, 2006


2008 ...

2010 ...

2015 ...

External Links