Changes

a [[Chess Engine Communication Protocol]] compatible chess engine by [[Roland Pfister]], later versions were [[UCI]] compliant, featuring a [[Parallel Search|parallel search]] and own [[Endgame Bitbases|endgame bitbases]], and were able to play [[Chess960]] <ref>[http://web.archive.org/web/20090430124900/http://www.superchessengine.com/patzer.htm Patzer 3.80], [https://en.wikipedia.org/wiki/Wayback_Machine Wayback Machine]</ref>. Patzer is famous for solving the [[Behting Study]] <ref>[http://www.rebel.nl/authors.htm Meet the Authors - PATZER, Roland Pfister] hosted by [[Ed Schroder|Ed Schröder]]</ref> <ref>[https://www.stmintz.com/ccc/index.php?id=259020 Re: Position solved] by [[Roland Pfister]], [[CCC]], October 14, 2002</ref> and a special [[Draw|draw heuristic]] for checking sequences. Patzer was available as [[ChessBase#YoungTalents|Young Talent]] by [[ChessBase]] running under the [[Fritz#FritzGUI|Fritz6 GUI]] <ref>[http://www.chessbase.com/support/support.asp?pid=100 Support - ChessBase, May 28th, 2000] (dead link)</ref>.

At the moment I am working on including [[Endgame Tablebases|endgame table base]] support. Patzer has a text interface a well as [[GUI|GUIs]] for [[MS-DOS|DOS]], [[Windows]], OS/2 and [[X11]]. It can read/write [[Portable Game Notation|PGN]] and [[Extended Position Description|EPD]] files. It has an Interface for [[Auto232|Autoplayer232]] and for [[XBoard]]/[[WinBoard]]. It has knowledge of the [[Wrong color Color Bishop and Rook Pawn|"wrong" bishop]] in endgames. A [https://en.wikipedia.org/wiki/Hypertext Hypertext] User Online Manual is available in German for [[MS-DOS|DOS]], [[Windows]], OS/2 and [[Unix]].

Patzer uses the standard [[Alpha-Beta|alpha-beta]] [[Principal Variation Search|PVS]] search, enhanced by [[Hash Table|hashtables]] (4 retries replacement scheme), [[Null Move Pruning|recursive nullmove]] ([[Depth Reduction R|R]]=2) with verification if only one piece present, special [[Pruning|pruning]] heuristic for [[Node Types#ALL|ALL-nodes]], various [[Extensions|extensions]]. It also uses a special [[Material Hash Table|material hash table]] to adjust the [[Material|material]] balance values for certain [[Endgame|endgames]] where the "usual" values do not apply. It values [[King Safety|king safety]] and [[Passed Pawn|passed pawns]] rather high (too high?). It is a [[Incremental Updates|incremental]] [[Bitboards|bitboard]] program with [[Attack and Defend Maps|attack tables]] that are also used during [[Move generationGeneration|move generation]] and [[Move Ordering|sorting]].

* [http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=35220&p=133316 Is there a Tournament book for Patzer?] by [[Günther SimonrSimon]], [[Computer Chess Forums|Winboard Forum]], December 05, 2001* [https://www.stmintz.com/ccc/index.php?id=259020 Re: Position solved] by [[Roland Pfister]], [[CCC]], October 14, 2002 » [[Behting Study]]