Double Null Move
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Double Null Move,
a Null Move Pruning technique proposed by Vincent Diepeveen in 1997 [1], 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 [2], and was widely discussed in computer chess forums [3], and overall recognized as a great idea [4] . While likely too expensive in the middlegame where zugzwang is rare, and still not recommend for pawn endings [5], it might be well applied in other endgames.
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: 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
- Re: Search-algorithm by Don Dailey, CCC, August 01, 2009
- Why not two consecutive null moves ? by Henk van den Belt, CCC, May 07, 2015
References
- ↑ Re: Null move? by Vincent Diepeveen, rgcc, October 11, 1997
- ↑ Pseudo C code for double nullmove + PVS by Vincent Diepeveen, CCC, August 06, 2000
- ↑ Searching correctly with the Nullmove ==> no zugzwang problems anymore by Vincent Diepeveen, rgcc, October 23, 1997
- ↑ Re: Double Nullmove by James Swafford, CCC, March 30, 2001
- ↑ Re: double nullmove?? by Vincent Diepeveen, CCC, August 06, 2000