Changes

The '''Hash Move''' is a move probed from the [[Transposition Table|transposition table]], either a [[Best Move|best move]] of a stored [[Node Types#PV|PV-node]] - a [[PV-Move|PV-move]], or a good enough [[Refutation Move|refutation move]] to cause a [[Beta-Cutoff|cutoff]]. This move should most importantly searched first <ref>but usually after trying the [[Null Move]] of the [[Null Move Pruning|Null Move Heuristic]]</ref> <ref> [http://www.talkchess.com/forum/viewtopic.php?t=64093 tt move vs null move] by [[Erin Dame]], [[CCC]], May 27, 2017</ref>. One may save the [[Move Generation|move generation]] at all, if the hash move actually [[Fail-High|fails high]]. To guard against rare [[Transposition Table#KeyCollisions|TT key collisions]], one may apply a [[Legal Move|legality test]] of the hash move <ref>[[Robert Hyatt]], [[Anthony Cozzie]] ('''2005'''). ''[http://www.cis.uab.edu/hyatt/collisions.html The Effect of Hash Signature Collisions in a Chess Program]''. [[ICGA Journal|ICGA Journal, Vol. 28., No. 3]]</ref>.