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GerdIsenberg
Apr 23, 2018
[[toc]] **[[Home]] * [[Engines]] * chess22k** **chess22k**, an [[UCI]] compliant [[Open Source Engines|open source chess engine]] by [[Sander Maassen vd Brink]], written in [[Java]] first released in January 2017 <ref> [[http://open-chess.org/viewtopic.php?t=3068|chess22k v1.0]] by [[Sander Maassen vd Brink|sandermvdb]], [[Computer Chess Forums|OpenChess Forum]], January 13, 2017</ref>. While already in the 2400 Elo range using a 64-bit [[https://en.wikipedia.org/wiki/Java_virtual_machine|Java Runtime Environment (JRE)]], it has not initially implemented a [[Tapered Eval|tapered evaluation]], but abrupt transition based on piece counts per side to distinguish between [[Middlegame|middlegame]] and [[Endgame|endgame]] terms <ref>public boolean isEndGame(int color) in [[https://github.com/sandermvdb/chess22k/blob/master/src/main/java/nl/s22k/chess/ChessBoard.java|chess22k/ChessBoard.java at master · sandermvdb/chess22k · GitHub]]</ref> <ref>isEndGame used in [[https://github.com/sandermvdb/chess22k/blob/master/src/main/java/nl/s22k/chess/eval/EvalUtil.java|chess22k/EvalUtil.java at master · sandermvdb/chess22k · GitHub]]</ref>. However, tapered evaluation was implemented in chess22k **1.5** along with new evaluation terms adjusted by [[Texel's Tuning Method|Texel's tuning method]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=64869|chess22k 1.5 released]] by [[Sander Maassen vd Brink]], [[CCC]], August 12, 2017</ref>. In November 2017, chess22k had its over the board tournament debut, version **1.6** played the [[CSVN]] [[PT 52]] in Leiden, quite successful - shared 4th place with 6/9. Soon released afterwards, chess22k **1.6** requires [[Java#9|Java 9]] <ref>[[http://www.talkchess.com/forum/viewtopic.php?t=65714|chess22k 1.6 released]] by [[Sander Maassen vd Brink]], [[CCC]], November 13, 2017</ref>. =Features= <ref>Based on readme and [[https://github.com/sandermvdb/chess22k|GitHub - sandermvdb/chess22k]]</ref> ==[[Board Representation]]== * [[Bitboards]] * [[Magic Bitboards]] ==[[Search]]== * [[Iterative Deepening]] * [[Aspiration Windows]] * [[Principal Variation Search]] * [[Transposition Table]] * [[Move Ordering]] ** [[History Heuristic]] ** [[Internal Iterative Deepening]] ** [[Killer Heuristic]] * [[Selectivity]] ** [[Null Move Pruning]] ** [[Late Move Reductions]] ** [[Static Exchange Evaluation|SEE Pruning]] ==[[Evaluation]]== * [[Evaluation Hash Table]] * [[Tapered Eval]] 1.5 * [[Material]] * [[Bishop Pair]] * [[Piece-Square Tables]] * [[Mobility]] ** [[Trapped Pieces]] ** [[Rook on Open File|Rooks on (Semi) Open Files]] * [[Outposts]] * [[Pawn Hash Table]] * [[Pawn Structure]] ** [[Doubled Pawn]] ** [[Isolated Pawn]] ** [[Passed Pawn]] * [[King Safety]] ** [[King Safety#PawnShield|Pawn Shelter]] * [[Tactics|Tactical Penalties]] ** [[Check|In Check]] ** [[Hanging Piece|Hanging Pieces]] ** [[Pin|Pinnned Pieces]] * [[Texel's Tuning Method]] =Forum Posts= ==2017== * [[http://open-chess.org/viewtopic.php?t=3068|chess22k v1.0]] by [[Sander Maassen vd Brink|sandermvdb]], [[Computer Chess Forums|OpenChess Forum]], January 13, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=63118|New release: chess22k v1.1]] by [[Sander Maassen vd Brink]], [[CCC]], February 09, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=63496|chess22k 1.2 released]] by [[Sander Maassen vd Brink]], [[CCC]], March 19, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=63835|chess22k 1.3 released]] by [[Sander Maassen vd Brink]], [[CCC]], April 26, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=64189|Texel tuning method question]] by [[Sander Maassen vd Brink]], [[CCC]], June 05, 2017 » [[Texel's Tuning Method]] * [[http://www.talkchess.com/forum/viewtopic.php?t=64310|Impressive Texel-tuning results]] by [[Sander Maassen vd Brink]], [[CCC]], June 16, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=64337|chess22k 1.4 released]] by [[Sander Maassen vd Brink]], [[CCC]], June 18, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=64869|chess22k 1.5 released]] by [[Sander Maassen vd Brink]], [[CCC]], August 12, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=65714|chess22k 1.6 released]] by [[Sander Maassen vd Brink]], [[CCC]], November 13, 2017 * [[http://www.talkchess.com/forum/viewtopic.php?t=66171|chess22k 1.7 released]] by [[Sander Maassen vd Brink]], December 28, 2017 ==2018== * [[http://www.talkchess.com/forum/viewtopic.php?t=66282|chess22k progress overview]] by [[Sander Maassen vd Brink]], January 09, 2018 * [[http://www.talkchess.com/forum/viewtopic.php?t=66727|chess22k 1.8 released]] by [[Sander Maassen vd Brink]], [[CCC]], March 04, 2018 * [[http://www.talkchess.com/forum/viewtopic.php?t=67206|chess22k 1.9 released]] by [[Sander Maassen vd Brink]], [[CCC]], April 23, 2018 =External Links= * [[https://github.com/sandermvdb/chess22k|GitHub - sandermvdb/chess22k]] * [[http://www.computerchess.org.uk/ccrl/404/cgi/engine_details.cgi?print=Details&eng=chess22k%201.4%2064-bit|chess22k 1.4 64-bit]] in [[CCRL|CCRL 40/4]] =References= <references /> =What links here?= [[include page="chess22k" component="backlinks" limit="40"]] **[[Engines|Up one Level]]**