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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

Forum Posts


  1. ^ Re: Null move? by Vincent Diepeveen, rgcc, October 11, 1997
  2. ^ Pseudo C code for double nullmove + PVS by Vincent Diepeveen, CCC, August 06, 2000
  3. ^ Searching correctly with the Nullmove ==> no zugzwang problems anymore by Vincent Diepeveen, rgcc, October 23, 1997
  4. ^ Re: Double Nullmove by James Swafford, CCC, March 30, 2001
  5. ^ Re: double nullmove?? by Vincent Diepeveen, CCC, August 06, 2000

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