Gerd Isenberg wrote:Yes, first published 1975 in English by the Kaissa authors:hyatt wrote:I don't get the distinction in this case (Null move). We were USING null-move in 1989 WCCC as were at least a couple of others (LaChex comes to mind first). The deep Thought guys also reported on their results using it, and was the place where I first saw the TT avoid-null-move trick mentioned as well. This was not a 1995 thing. It was already well-known by then.
Georgy Adelson-Velsky, Vladimir Arlazarov and Mikhail Donskoy (1975). Some Methods of Controlling the Tree Search in Chess Programs. Artificial Ingelligence, Vol. 6, No. 4, pp. 361-371. ISSN 0004-3702. Reprinted (1988) in Computer Chess CompendiumOn Lachex, it appears in the WCCC 1989 booklet under program descriptions with null move mentioned (pp 15), but not in the table of participants and Lachex did not play in Edmonton (it played 1986 in Cologne and 1992 Madrid).2. The Order of Move Considerations:
A less trivial idea was that sometimes an extension of the game tree by introducing of dummy move can lead to a reduction of the search tree. In positions with material advantage (with respect to limits) it was permitted to try a so-called "blank" move in which ones own pieces are not moved. Certainly in positions with "Zugzwang" (the side to move must weaken his position) this may lead to errors.
http://archive.computerhistory.org/proj ... 028.sm.pdf
Didn't Cray Blitz already use null move in 1983, according to your 1996 rgcc post? I mean that is no contradiction CB used null move in 1989 as well, but one then assumes 1989 was the first occurrence using null move.
http://groups.google.com/group/rec.game ... dc1ec60967Null Move was used in 1983, because I used it in the program that won the world computer chess championship that year. They aren't particularly new ideas at all ...
I don't think what they do is based on the "Null Move assumption" as defined by Beal. You can find a 1974 or so paper about my original Blitz program that talked about using a null-move. But it was used to deal with threats. I played a null-move, and let the tactical component of my search find the best tactical shot (if present). I could then fairly safely assume I could remove THAT threat by playing a real move. If the opponent had ANOTHER tactical shot, then I was in trouble and needed more search. Not the same as the null-move observation to refute anything. In fact, my null-move search didn't fail high or low in Blitz IV (very selective program as was common in early 70's). But I had a "causality function" (similar to Berliner's idea described in his "Chess as problem solving, the development of ..." paper. It could take a PV and figure out what was wrong, but it needed a PV to workon. This was a cheap way to detect the opponent's threats in the days when FORTRAN was not even close to being recursive.