Zappa is a chess engine, or a program that plays chess. It is similar to Deep Blue - only much better - and is best known for its good parallel speedup. It has competed in many computer chess tournaments with its best result coming at the World Computer Chess Championship in 2005, where it took first place with the score of 10.5 / 11. Like Fritz or Shredder, it is a standard chess engine, which in technical terms means it is a brute force alpha-beta searcher with a heuristical evaluation. You can buy a copy here.


The Zappa project is 100% finished. This includes both tournaments and future releases.

Tournament Results

Overall, Zappa's standard time tournament record stands at 67 wins, 37 draws, and 11 losses (74.3%, a record most professional sports teams would envy) with three titles, one world championship, two match victories, and 10000$ in prize money. Aside from the for-fun internet tournaments (CCT), Zappa has never lost a game to anyone or anything not named Rybka. All Games


Zappa is not named for the great Frank Zappa, or at least not directly. I got the name from Austin Powers 2, which has a scene where Dr. Evil talks about how he has divided his moon base into "Moon Unit Alpha" and "Moon Unit Zappa", a pun on Frank's quixotically named daughter Moon Unit. I have never listened to his music, although I like many of his quotes. Interestingly, Frank liked chess and used to play with the band quite a bit.


Zappa Mexico can be used on Windows or Linux computers with up to 512 CPU cores. Unfortunately, the parallel implementation relies on shared memory, so you cannot hook two computers together with an ethernet cable and use them together, unless you are willing to give SGI several hundred thousand dollars. Zappa Mexico also supports multipv analysis, Nalimov tablebases, and as a UCI engine it can be used in most of the standard chess GUIs. To the best of my knowledge, not a single computer has caught fire while running Zappa.

Great Moves

Unfortunately in computer chess games most of the beautiful combinations occur in the notes. Chess engines are simply so strong tactically that they almost never fall into traps. Still, here are a few tricks from the good old days.

1rb2rk1/4R1p1/1pqn1pBp/3p4/5Q2/1NP3PP/6PK/4R3 w - - 0 30

From Zappa-Searcher, CCT6. Here Be8 wins the exchange, but R1e6!! wins overwhelmingly. The game continued 30. Re6 Bxe6 31. Nd4 Qc4 32. Qxd6 Bxh3 33. Kxh3 Kh8 35. Nf5 and it is obvious Zappa's attack is too strong for Black to survive.

4r1k1/3R3p/p5p1/n3r1q1/8/P1Q5/1P6/KB1R4 w - - 0 43

From Zappa-Crafty, 2005 World Computer Chess Championship in Reykjavik. Here Zappa played the elegant Re1! (Rxe1 Qg7, and White threatens Qxa5 Rxa5 Rxe8) and the game continued 43... Qf6 44. Rxe5 Qxe5 45. Ba2 Kh8 46. Rd8! 1-0. This is a relatively easy combination for a modern program, but it's still pretty.


Anthony Cozzie

David Dahlem

David Dahlem

Wilhelm Hudetz

Jim Ablett

Stefan Persson

Graham Banks

Benjamin Händel


Zappa is written entirely by me, Anthony Cozzie, but I have received a great deal of help from (in no particular order) Arturo Ochoa, Bob Hyatt, Bruce Moreland, Ed Schroeder, Erdogan Günes, Gunther Simon, Harvey Williamson, Jay Urbanski, Marek Baron, Stefan Meyer-Kahlen, Tord Romstad, Will Singleton, Vincent Diepeveen, Volker Pittlik, and Volker Richey.


Zappa Mexico is commercial. You can buy a copy here. However, you can download an older version for free. It is a command line program without a graphical chessboard, so if the idea of typing commands by hand does not appeal to you, you will need to download a GUI. Arena is free; the commercial Chessbase (Fritz), Shredder, and ChessPartner GUIs should also work. For all you old-schoolers, Zappa does support WB2 and will work in XBoard or WinBoard. If you want to run engine-engine matches, you will also need to supply an opening book.