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Subject: Re: not using nullmove?

Author: Tord Romstad

Date: 09:03:03 02/17/04

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On February 17, 2004 at 08:19:28, martin fierz wrote:

>On February 17, 2004 at 07:55:32, Tord Romstad wrote:
>>KR vs KP is a difficult one.  Does anybody have any good suggestions about
>>how to evaluate it?  At the moment I don't have any specific code for this
>>endgame at all, and Gothmog almost always evaluates it as a win for the rook.
>>In reality, it is of course very often a draw.
>i'll have to think about this one too. i haven't done either KR-KP or KQ-KP;
>KQ-KP should be rather easy as there are basically only two drawing positions;

Yes.  KQ-KP is much easier, and also less important, because the probability
of a draw is much smaller here.

>KR-KP is much harder. but you should at least be able to easily identify many
>cases where KR is clearly winning; e.g. any time the KR-side king is in the
>square of the pawn KR is winning (with one exception: wKe2, bPd2, bKf1/f2, black
>to move, but qsearch should catch that).

This is a good start, but I think it might be more valuable to work
from the other end:  Which positions do we know are drawn?  I guess
the probability of a draw is big if the pawn is on the fifth rank or
beyond and supported by the king, and the attacking king is far away.
But this is certainly too simple to be a sure drawing rule.

There is also not many clear rules to be found in Keres' "Practical
Chess Endings" (my main endgame reference), which makes me fear that
it is not easy to evaluate this endgame correctly.


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