Author: Dieter Buerssner
Date: 09:32:32 10/19/00
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On October 19, 2000 at 11:10:53, Uri Blass wrote: >On October 19, 2000 at 09:18:45, Dieter Buerssner wrote: > >>On October 18, 2000 at 14:14:20, Uri Blass wrote: >> >>>I can give another rule: >>>Blacks draw if it is black to move and the distance between the black king and >>>the corner in king moves is smaller than the ditance between the corner and the >>>white pieces except the bishop(white king in king moves and white pawn in pawn >>>moves) >>> >>>If it is white to move then use distance-1 instead of distance for white. >>Rarely, your rule predicted a draw, when the position is lost. And this was wrong, sorry. I did not implement the rule exactly as written above. By an oversight, I rather used smaller or equal instead of smaller, because this was more or less similar to what I allready had. >No my rule does not say that it is a draw because the distance of the king to >the corner is equal and not smaller then the distance of the pawn. > >I guess that in most of the cases when the distance is equal it is a draw but my >rule was made to be always correct when it says draw. Also this is correct, when I did not make another stupid mistake. I tested all KBPK positions with an h pawn and the wrong bishop. There were 639768 different positions (a value pretty close to an estimate of 64*55*32*6). Of those, there are 233366 draws due to TBs. Your rule did not predict any position as draw, that is lost for black. I also supplemented your rule by the rule given by Ricardo and I think Bruce, namely that when the black king is on g/h 7/8, it is a draw. This gives a slightly better success rate. With this, the rule returns "may be lost" in 114475 cases, that are draw. Just out of curiosity, I also made the same test with smaller or equal. Then exactly 5049 are predicted wrongly as draws. "May be lost" is returned in 66599 cases, that are draws. >It is possible to do a rule that is 100% correct when it says win when the other >positions can be divided to probably draw and probably win for white but I did >not do it. I wouldn't mind to hear from your next rule ;) Thanks again, Dieter
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