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Created page with "'''Home * Chess * Moves * Hash Move''' ''The '''Hash Move''' is a Move Ordering related issue.'' The '''Hash Move''' is a move probed from the Tr..."
'''[[Main Page|Home]] * [[Chess]] * [[Moves]] * Hash Move'''
''The '''Hash Move''' is a [[Move Ordering]] related issue.''
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]], 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>.
=See also=
* [[Best Move]]
* [[Killer Move]]
* [[Mate Killers]]
* [[Move Ordering]]
* [[Null Move]]
* [[Pseudo-Legal Move]]
* [[PV-Move]]
* [[Refutation Move]]
* [[Threat Move]] from [[Null Move Pruning|null move]] refutations
* [[Transposition Table]]
: [[Transposition Table#Collisions|Collisions]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?t=63090 TTMove legality checking ? & Killers Move Format?] by [[Mahmoud Uthman]], [[CCC]], February 08, 2017 » [[Killer Move]]
* [http://www.talkchess.com/forum/viewtopic.php?t=64093 tt move vs null move] by [[Erin Dame]], [[CCC]], May 27, 2017 » [[Null Move]], [[Null Move Pruning]]
* [http://www.talkchess.com/forum/viewtopic.php?t=65189 Marginal hash move] by [[Harm Geert Muller]], [[CCC]], September 16, 2017
=References=
<references />
'''[[Moves|Up one Level]]'''
''The '''Hash Move''' is a [[Move Ordering]] related issue.''
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]], 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>.
=See also=
* [[Best Move]]
* [[Killer Move]]
* [[Mate Killers]]
* [[Move Ordering]]
* [[Null Move]]
* [[Pseudo-Legal Move]]
* [[PV-Move]]
* [[Refutation Move]]
* [[Threat Move]] from [[Null Move Pruning|null move]] refutations
* [[Transposition Table]]
: [[Transposition Table#Collisions|Collisions]]
=Forum Posts=
* [http://www.talkchess.com/forum/viewtopic.php?t=63090 TTMove legality checking ? & Killers Move Format?] by [[Mahmoud Uthman]], [[CCC]], February 08, 2017 » [[Killer Move]]
* [http://www.talkchess.com/forum/viewtopic.php?t=64093 tt move vs null move] by [[Erin Dame]], [[CCC]], May 27, 2017 » [[Null Move]], [[Null Move Pruning]]
* [http://www.talkchess.com/forum/viewtopic.php?t=65189 Marginal hash move] by [[Harm Geert Muller]], [[CCC]], September 16, 2017
=References=
<references />
'''[[Moves|Up one Level]]'''
