Changes

[[FILE:EschersRelativity.jpg|border|right|thumb|link=http://www.mcescher.com/Gallery/back-bmp/LW389.jpg|[[Arts#:Category:M. C. Escher|M. C. Escher]], Relativity, 1953 <ref>[http://www.mcescher.com/Gallery/gallery-back.htm Picture gallery "Back in Holland 1941 - 1954"] from [http://www.mcescher.com/ The Official M.C. Escher Website]</ref> ]]

Futility pruning is not used when the [[Side to move|side to move]] is in [[Check|check]] , or when either [[Alpha|alpha]] or [[Beta|beta]] are close to the [[Checkmate#MateScore|mate value]], since it would leave the program blind to certain [[Checkmate|checkmates]]. [[Tord Romstad]] reported that in his early program [[Gothmog]] one more condition was necessary - namely that futility pruning requires checking for the existence of at least one legal move <ref>[http://www.open-aurec.com/wbforum/viewtopic.php?f=18&t=43669&p=166791 Serious bug in Gothmog 0.2.6!] by [[Tord Romstad]], [[Computer Chess Forums|Winboard Forum]], August 04, 2003</ref> <ref>[https://www.stmintz.com/ccc/index.php?id=339076 Re: Unexpected problem with futility pruning?] by [[Tord Romstad]], [[CCC]], December 29, 2003</ref> to avoid returning erroneous stalemate scores. As replied by [[Eli David|Omid David]]: then simply return alpha (to fail [[Fail-Low|low]] but [[Fail-Hard|hard]]).

* [[Ernst A. Heinz]] ('''1998'''). ''[http://people.csail.mit.edu/heinz/dt/node18.html Extended Futility Pruning].'' [[ICGA Journal#21_2|ICCA Journal, Vol. 21, No. 2]]* [[Jeroen Carolus]] ('''2006''').''Alpha-Beta with Sibling Prediction Pruning in Chess''. Masters thesis, [http://homepages.cwi.nl/%7Epaulk/theses/Carolus.pdf pdf]* [[Kunihito Hoki]], [[Masakazu Muramatsu]] ('''2012'''). ''[https://www.semanticscholar.org/paper/Efficiency-of-three-forward-pruning-techniques-in-Hoki-Muramatsu/206099961f401c8693e071c2b739f164ae5ffa6c Efficiency of three Forward-Pruning Techniques in Shogi: Futility Pruning, Null-move Pruning, and Late Move Reduction (LMR)]''. [https://www.journals.elsevier.com/entertainment-computing Entertainment Computing], Vol. 3, No. 3

* [http://www.talkchess.com/forum/viewtopic.php?t=43513 A search enhancement?] by [[Dan Homan|Daniel Homan]], [[CCC]], April 30, 2012 » [[Futility Pruning#MoveCountBasedPruning|Move Count Based Pruning]]

* [[Videos#PorcupineTree:Category:Porcupine Tree|Porcupine Tree]] - [https://en.wikipedia.org/wiki/Futile_(EP) Futile], [https://de.wikipedia.org/wiki/Zeche_Bochum Zeche] [https://en.wikipedia.org/wiki/Bochum Bochum], November 18, 2003, [https://en.wikipedia.org/wiki/YouTube YouTube] Video