Author: Uri Blass
Date: 23:48:35 06/15/03
Go up one level in this thread
On June 16, 2003 at 00:57:16, Harald Faber wrote:
>On June 15, 2003 at 15:59:25, Dieter Buerssner wrote:
>
>>On June 15, 2003 at 13:00:40, Harald Faber wrote:
>>
>>>8/8/8/5k2/1pK4P/6P1/8/4b3 b - - 0 1
>>>
>>>Only 6 pieces and not far from the tablebases. But which programs find the
>>>winning idea? You see it when playing through because 1.Kg4 is found by
>>>programs. But which play the king manoeuvre and don't play stupid bishop moves?
>>
>>In a small test vs. myself, Yace would win. It does not mean much of course. But
>>I think, it would win this vs. any opponent (it might insert some useless
>>moves). I am not good enough to judge longer PVs blind and did not check enough
>>of the PVs shown by analysis of the root positions. Also sometimes they are too
>>short or out of HTs (after all, typically chess engines are not optimized to
>>show long and reliable PVs).
>>
>>But I can prove (needed perhaps 20 minutes) that with Kg4 black can announce a
>>mate in 24 (it could be a faster mate):
>>
>> 252678 0.967 Mat24 17t 1...Kg4 2. Kb3 Bd2H 3. Ka4H Bc3H 4. Kb3H Kf3H
>> 5. Ka4H Ke3H 6. h5H Kd2H 7. Kb3H Kd3H 8. h6H
>> Kd4H 9. h7H Kc5H 10. g4H Bh8H 11. g5H Bd4H 12.
>> Ka4H Bg1H 13. h8=QH Be3H {HT}
>>
>>Note that most moves are out of hash tables (the ones with H attached). Those
>>are not necessarily reliable (however the further up ones should be rather
>>reliable). The score must be reliable nevertheless.
>>
>>Regards,
>>Dieter
>
>Did you notice that in this line the idea with the king is OK but that white
>gets a queen with 13.h8-Q and black cannot capture this piece?
>Maybe you should play through this line, I am sure Yace will find the right
>moves then too, because up to move 9 everything is fine.
Did you notice the letter H?
I understood that it means that the moves were constructed from hash tables and
cannot be trusted.
Note that I have no idea what is the way of chess programs to use hash tables to
construct pv lines and the only clear thing is that it leads often to wrong
results(I am sure that yace does not remember mate score for black after
13.h8=Q).
Uri
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