Editing Chess endgame (section)

==Longest known forced win==
{{See also|Endgame tablebase#Endgame theory}}
{{Update section|date=November 2023|reason=New record was discovered in 2021}}{{col-begin|width=auto; float:left; clear:left}}
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{{Chess diagram  
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|  |  |  |  |  |  |  |  
|  |rd|  |  |  |  |  |
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |nd|  
|  |  |  |  |  |kd|  |  
|  |bd|  |  |  |  |  |  
|  |  |  |kl|  |  |  |nl
|  |  |  |  |  |  |  |ql
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Black's best move in this position is 1...Rd7+. White mates 545 moves later. }}
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{{Chess diagram  
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|  |nd|  |kd|  |  |  |  
|  |  |  |  |  |  |ql|  
|  |  |  |  |  |kl|pl|  
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |  |bd
|  |rd|  |  |  |  |  |  
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |  |  
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White to play mates in 549 moves. }}
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{{Chess diagram  
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|rl|  |  |  |  |  |  |  
|  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |  |  
|  |  |  |  |  |  |  |qd  
|  |  |kl|  |bl|  |  |pd  
|  |  |  |  |  |  |  |pl
|  |  |bl|kd|  |  |  |
|White can capture Black's queen in 584 moves, starting with 1. Rf8.<ref>{{cite web |last1=Silver |first1=Albert |title=8-piece endgame tablebases - first findings and interview! |url=https://en.chessbase.com/post/8-piece-endgame-tablebases-first-findings-and-interview |website=ChessBase |date=11 May 2022 |access-date=2 January 2024}}</ref> (The resulting position is an easy win for White.)
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In May 2006 a record-shattering 517-move endgame was announced (see first diagram). Marc Bourzutschky found it using a program written by Yakov Konoval. Black's first move is '''1... Rd7+''' and White wins the rook in 517 moves. This was determined using the easier-to-calculate [[Endgame tablebase#Metrics|depth-to-conversion]] method, which assumes that the two sides are aiming respectively to reduce the game to a simpler won ending or to delay that conversion. Such endgames do not necessarily represent strictly optimal play from both sides, as Black may delay checkmate by allowing an earlier conversion or White may accelerate it by delaying a conversion (or not making one at all). In September 2009, it was found that the distance to ''mate'' (not conversion) in that position was 545 (see the first diagram).<ref>[http://chessok.com/?page_id=27966 Lomonosov Endgame Tablebases]</ref> The same researchers later confirmed that this (along with variations of it) is the longest seven-piece pawnless endgame, and that, with pawns, the longest seven-piece endgame is the one depicted in the second diagram. White takes 6 moves to promote the pawn to a Knight (leading to a position similar to the first diagram), after which it takes another 543 moves to win the game, for a total of 549 moves.<ref>{{Cite web |url=http://ldis-sw.cs.msu.ru/articles/Top8DTM_eng |title=Articles |access-date=2014-09-19 |archive-date=2016-11-17 |archive-url=https://web.archive.org/web/20161117145244/http://ldis-sw.cs.msu.ru/articles/Top8DTM_eng |url-status=dead }}</ref> 

The [[fifty-move rule]] was ignored in the calculation of these results and lengths, and as of 2014, these games could never occur, because of the [[seventy-five-move rule]].