Mate+Threat+Extensions

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 * Mate Threat Extensions** are extensions caused by a mate threat of the opponent detected after making a null move in a fail-soft framework, or alternatively with a low shifted, or full window. Some programs detect mate in one threats statically, i.e. as part or byproduct of king safety in evaluation, to extend near or at the horizon.

=Threat Extensions= Mate threat extensions are special cases of the more general //Threat extensions// not only restricted to mate scores but losing some material. According to Ernst A. Heinz, the Deep Thought team already used fail-low null move scores to detect threats before 1990, descibed by Thomas Anantharaman in his thesis and ICCA Journal paper , where he mentioned fall 1986 implementation in ChipTest.

Deep-Search Extensions
The term //Deep-search extension// was coined by Chrilly Donninger in his //Null Move and Deep Search// paper. As pointed out by Ernst A. Heinz, Donninger's idea was to extend the search by one ply if a null move near the horizon does not fail high and the null move score plus a constant margin is below alpha, while the static evaluation indicates a fail high. He further states :

DarkThought
Citing //How DarkThought Plays Chess// :

=See also=
 * Botvinnik-Markoff Extension
 * Mate Killers
 * Threat Detection

=Publications=
 * Thomas Anantharaman (**1990**). //A Statistical Study of Selective Min-Max Search in Computer Chess//. Doctoral Thesis. UMI Order Number: AAI9111467, Carnegie Mellon University
 * Thomas Anantharaman (**1991**). //Extension Heuristics//. ICCA Journal, Vol. 14, No. 2, pp. 47-65
 * Chrilly Donninger (**1993**). //Null Move and Deep Search: Selective-Search Heuristics for Obtuse Chess Programs.// ICCA Journal, [|Vol. 16, No. 3], pp. 137-143
 * Ernst A. Heinz (**1997**). //[|How DarkThought Plays Chess].// ICCA Journal, Vol. 20, No. 3, pp. 166-176 » [|Extension Heuristics]

=Forum Posts= > [|Re: mate threat extension/null move] by Don Beal, CCC, October 04, 2004 » WAC booster
 * [|Deep Search Extension] by Stuart Cracraft, CCC, January 18, 1998
 * [|Null move mate extension] by James Robertson, CCC, June 25, 1999
 * [|The "same threat extension" as effective way to resolve horizon problem] by Sergei Markoff, CCC, October 01, 2003
 * [|mate threat extension/null move] by Rick Bischoff, CCC, September 25, 2004
 * [|null move threat extension] by Andrew Short, CCC, October 23, 2008

=External Links=
 * [|Extension Heuristics] from Ernst A. Heinz (**1997**). //[|How DarkThought Plays Chess].// ICCA Journal, Vol. 20, No. 3, pp. 166-176
 * [|Programming Details - Slow Chess | Extensions Used, Detailed Description] by Jonathan Kreuzer » Slow Chess

=References= =What links here?= include page="Mate Threat Extensions" component="backlinks" limit="40"
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