Editing Computer chess (section)

== Computer chess rating lists ==
{{see also|Chess engine#Ratings}}
[[Chess Engines Grand Tournament|CEGT]],<ref>{{Citation | url=http://www.husvankempen.de/nunn/rating.htm | title=CEGT 40/20 | date=12 October 2008 | publisher=[[Chess Engines Grand Tournament]] | access-date=21 October 2008 | archive-url=https://web.archive.org/web/20120301182317/http://www.husvankempen.de/nunn/rating.htm | archive-date=1 March 2012 | url-status=dead | df=dmy-all }}</ref> CSS,<ref>{{Citation | url=http://www.computerschach.de/index.php?option=com_wrapper&Itemid=242 | title=Computerschach und Spiele – Eternal Rating | date=18 March 2007 | publisher= Computerschach und Spiele | access-date=21 May 2008}}</ref> [[Swedish Chess Computer Association|SSDF]],<ref>{{Citation | url=http://ssdf.bosjo.net/list.htm | title=The SSDF Rating List | publisher=[[Swedish Chess Computer Association]] | date=26 September 2008 | access-date=20 October 2008}}</ref> WBEC,<ref>{{Citation | url=http://wbec-ridderkerk.nl/html/BayesianElo_ed15.htm | title=BayesianElo Ratinglist of WBEC Ridderkerk | access-date=20 July 2008}}</ref> [[REBEL (chess)|REBEL]],<ref>{{cite web | url=https://rebel13.nl/misc/gambit-rating-list.html | title=Gambit Rating List | publisher=Home of the Dutch Rebel | date=January 30, 2021 | access-date=December 12, 2021}}</ref> FGRL,<ref>{{cite web | url=http://fastgm.de | title=FGRL | publisher=FastGM's Rating List |  access-date=December 12, 2010}}</ref> and IPON<ref>{{cite web | url=http://www.inwoba.de/bayes.html | title=IPON | publisher=Ingo Bauer | date=November 16, 2016 | access-date=February 3, 2016 | archive-url=https://web.archive.org/web/20190125041233/http://inwoba.de/bayes.html | archive-date=January 25, 2019 | url-status=dead }}</ref> maintain rating lists allowing fans to compare the strength of engines. Various versions of [[Stockfish (chess)|Stockfish]], [[Komodo (chess)|Komodo]], [[Leela Chess Zero]], and [[Fritz (chess)|Fat Fritz]] dominate the rating lists in the early 2020s.

CCRL  (Computer Chess Rating Lists) is an organisation that tests computer [[chess engine]]s' [[Elo rating system|strength]] by playing the programs against each other. CCRL was founded in 2006 to promote computer-computer competition and tabulate results on a rating list.<ref name=CCRL>CCRL, http://ccrl.chessdom.com/ {{Webarchive|url=https://web.archive.org/web/20220121151824/http://ccrl.chessdom.com/ |date=2022-01-21 }}, 14 November 2021</ref>

The organisation runs three different lists: 40/40 (40 minutes for every 40 moves played), 40/4 (4 minutes for every 40 moves played), and 40/4 [[Chess960|FRC]] (same time control but Chess960).<ref group=Note name=Note1/> Pondering (or [[permanent brain]]) is switched off and timing is adjusted to the AMD64 X2 4600+ (2.4&nbsp;GHz) [[CPU]] by using [[Crafty 19.17 BH]] as a benchmark. Generic, neutral [[chess opening book|opening books]] are used (as opposed to the engine's own book) up to a limit of 12 moves into the game alongside 4 or 5 man [[tablebases]].<ref name=CCRL /><ref>CCRL Discussion Board, http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=7&t=2808, 19 June 2012</ref><ref>Adam's Computer Chess Pages, http://adamsccpages.blogspot.co.uk/2012/05/ccrl.html, 19 June 2012</ref>