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* moves that give [[Check|check]]
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]]).
<span id="Extendedfutilitypruning"></span>
=Extended Futility Pruning=
* [[Razoring]]
* [[Reverse Futility Pruning]]
* [[Sibling Prediction Pruning]]
=Publications=
* [[Chun Ye]], [[Tony Marsland]] ('''1992'''). ''Experiments in Forward Pruning with Limited Extensions.'' [[ICGA Journal#15_2|ICCA Journal, Vol. 15, No. 2]]
* [[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
