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a Chess Engine Communication Protocol compatible chess engine by Roland Pfister, later versions were UCI compliant, featuring a parallel search and own endgame bitbases, and were able to play Chess960 [1]. Patzer is famous for solving the Behting Study [2] [3] and a special draw heuristic for checking sequences. Patzer was available as Young Talent by ChessBase running under the Fritz6 GUI [4].

Tournament Play

Patzer played the WMCCC 1996 in Jakarta, the WMCCC 1997 in Paris, the WCCC 1999 in Paderborn, and the Chess960CWC 2005 and Chess960CWC 2006 in Mainz. Further, Patzer was active over the board at IPCCCs, the 5th Spanish Open Computer Chess Championship, Dutch Open Computer Chess Championships, International CSVN Tournaments, and the BELCT 2001.




Patzer uses state of the art methods as minimal window, hash tables, history table, static exchange evaluation with bitboards, various extensions, recursive nullmove . It has small databases for KPK and KPKP with blocked pawns to decide if it is a win or not. Additionally it can use Thompson's Endgame CDs at ply 0.
At the moment I am working on including endgame table base support. Patzer has a text interface a well as GUIs for DOS, Windows, OS/2 and X11. It can read/write PGN and EPD files. It has an Interface for Autoplayer232 and for XBoard/WinBoard. It has knowledge of the "wrong" bishop in endgames. A Hypertext User Online Manual is available in German for DOS, Windows, OS/2 and Unix. 


Patzer uses the standard alpha-beta PVS search, enhanced by hashtables (4 retries replacement scheme), recursive nullmove (R=2) with verification if only one piece present, special pruning heuristic for ALL-nodes, various extensions. It also uses a special material hash table to adjust the material balance values for certain endgames where the "usual" values do not apply. It values king safety and passed pawns rather high (too high?). It is a incremental bitboard program with attack tables that are also used during move generation and sorting. 



Patzer team Frank Quisinsky and Roland Pfister at ICT 2001 [6]

See also


Forum Posts

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External Links

Chess Engine


patzer - Wiktionary


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