Author: Christophe Theron
Date: 09:26:42 10/19/00
Go up one level in this thread
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.
>>
>>Uri, thank you very much, for giving your rule. Also thanks to all
>>the other answers to my questions.
>>
>>I have made a small experiment. I set up 10000 random positions
>>with a white pawn on h, the wrong bishop and the kings on two random
>>legal squares. Black to move.
>>Of the 10000 positions, 3716 where draws due to TBs.
>>I compared the result of your rule, and the result that is returned by TBs. Your
>>rule had an overall success rate of 90%.
>>At first sight, this might not look too good, but it will probably be
>>very good in practical play. I checked some of the positions, where the
>>"rule" failed. Most positions, where you rule failed, where when it predicted
>>a loss and the position is draw are trivial, because the Black king can capture
>>the pawn in the next move. So in a real game, the quiescence search would find
>>this immediately.
>>
>>In a few cases, the pawn can be captured the move after the next move,
>>and these are of course more dangerous. One example
>>
>>[D] 2B5/8/7P/5k2/8/8/3K4/8 b - - 0 0
>>
>>But again here, with the help of search, this will be found soon.
>>
>>Rarely, your rule predicted a draw, when the position is lost. But here the
>>success rate of your rule was almost 99%. (In 95 positions, your rule predicted
>>a wrong draw). One example:
>>
>>[D] 5k2/8/7P/8/8/8/B7/6K1 b - - 0 0
>
>
>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.
>
>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.
>
>Uri
Uri, when I think about it, it looks like your rule does not work if white has
several pawns in the A or H file.
Is it true?
Christophe
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