Author: Robert Hyatt
Date: 10:22:41 02/28/01
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On February 28, 2001 at 11:10:30, Miguel A. Ballicora wrote: >On February 28, 2001 at 05:56:36, Leen Ammeraal wrote: > >>I am not sure about when to avoid nullmoves. >>I omit it: >>a. when in check >>b. when there are less than 5 pieces (including pawns) on the board >>c. when the last move was a nullmove >>d. at the root node >>Should I also omit it in some other cases, >>for example, when any hashmove (even with a low draft) was found, >>or when beta = alpha + 1? >>Thanks in advance for any help. >>Leen > >Hi Leen, > >Regarding b, I do not know whether what I am doing now is correct but I think >that works for me: >When either black or white had no "long range" pieces (bishop, rook or queen) >I disable null move. The rationale is that one side cannot waste >a tempo in a given position having pawns, king and/or knights making the >position prone to have a zugswang. > >Miguel That seems dangerous. you are white, with a bishop on d5. I am black and I have a pawn on a7 and g7. The bishop is zugged here. If your king can't move, you lose even though you have a long-range slider on the board. And null move will fail high here naturally as not moving is better than having to move and lose.
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