Double+Null+Move

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a Null Move Pruning technique proposed by Vincent Diepeveen in 1997, that allows two consecutive null moves with common depth reduction R in a row. Provided that the depth or distance to the horizon is big enough to recognize a possible zugzwang 2R+2 plies shallower, and the first null move is refuted by the second one, its aim is to make NMH zugzwang aware. Double Null Move is used in Diep, and was widely discussed in computer chess forums , and overall recognized as a great idea. While likely too expensive in the middlegame where zugzwang is rare, and still not recommend for pawn endings, it might be well applied in other endgames.
 * Double Null Move**,

=See also=
 * Fail-High Reductions
 * Internal Iterative Deepening
 * Null Move
 * Null Move Observation
 * Null Move Reductions
 * Null Move Test-Positions, where Null Move may fail due to zugzwang
 * Zugzwang
 * Zugzwang Verification

=Forum Posts= > [|Re: Search-algorithm] by Don Dailey, CCC, August 01, 2009
 * [|Re: Null move?] by Vincent Diepeveen, rgcc, October 11, 1997
 * [|Searching correctly with the Nullmove ==> no zugzwang problems anymore] by Vincent Diepeveen, rgcc, October 23, 1997
 * [|Pseudo C code for double nullmove + PVS] by Vincent Diepeveen, CCC, August 06, 2000
 * [|Double Nullmove] by David Rasmussen, CCC, March 30, 2001
 * [|Double Null move?] by Steve Maughan, CCC, July 13, 2001
 * [|Double Nullmove] by Andreas Herrmann, CCC, April 25, 2002
 * [|double null move help] by Daniel Shawul, CCC, July 04, 2004
 * [|Re: Search-algorithm] by Vincent Diepeveen, CCC, August 01, 2009
 * [|Why not two consecutive null moves ?] by Henk van den Belt, CCC, May 07, 2015

=References= =What links here?= include page="Double Null Move" component="backlinks" limit="40"
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