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or its version known as '''History Pruning''' and '''History Reductions''' <ref>[http://members.home.nl/matador/hr.htm History Reductions in Pro Deo] by [[Ed Schroder|Ed Schröder]]</ref> , save search by reducing [[Moves|moves]] that are [[Move Ordering|ordered]] closer to the end of likely [[Node Types#ALL|fail-low nodes]]. Typically, most schemes search the first few moves (say 3-4) at full [[Depth|depth]], then if no move [[Fail-High|fails high]], many of the remaining moves are reduced in search [[Depth|depth]]. The technique has been used for many years in various forms, but it became very popular in 2005 after [[Fruit]] and [[Glaurung]] <ref>[https://web.archive.org/web/20150212051846/http://www.glaurungchess.com/lmr.html An Introduction to Late Move Reductions] by [[Tord Romstad]]([https://en.wikipedia.org/wiki/Wayback_Machine Wayback Machine])</ref> used open source implementations based on the [[History Heuristic]]. LMR can often reduce the [[Branching Factor#EffectiveBranchingFactor|effective branching factor]] to less than 2, depending on the reduction conditions.

* Moves with good past [[Relative History Heuristic|relative history]] <ref>[[Mark Winands]], [[Erik van der Werf]], [[Jaap van den Herik]], and [[Jos Uiterwijk]] ('''20062004'''). ''[http://link.springer.com/chapter/10.1007/11674399_18 The Relative History Heuristic]''. Computers and Games, Lecture Notes in Computer Science (LNCS 3846) (eds. [[Jaap van den HerikCG 2004]], [[Yngvi Björnsson]], and [[Nathan S. Netanyahu]]), pp. 262-272. [http://www.cserikvanderwerf.unimaastengen.nl/m.winands/documentspubdown/relhis.pdf pdf]</ref>

* [https://web.archive.org/web/20150212051846/http://www.glaurungchess.com/lmr.html An Introduction to Late Move Reductions] by [[Tord Romstad]] (dead link[https://en.wikipedia.org/wiki/Wayback_Machine Wayback Machine])* [http://mediocrechess.blogspot.de/2007/03/other-late-move-reduction-lmr.html Mediocre Chess: <nowiki>[Guide] </nowiki> Late move reduction (LMR)] by [[Jonatan Pettersson]], March 26, 2007 » [[Mediocre]]