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Subject: Re: Blitz tablebase ending problem

Author: Mike Hood

Date: 03:38:22 10/29/01

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On October 28, 2001 at 15:58:16, Uri Blass wrote:

>On October 28, 2001 at 13:30:12, Chessfun wrote:
>
>>[D]8/8/8/4b3/7k/7p/8/6K1 w - - 0 124
>>
>>In this position playing a blitz game
>>Gambit Tiger played 124. Kf2? then went
>>on to lose on move 131 on time.
>>
>>Yet I have all 5 piece tablebases installed.
>>If I load Gambit as with any engine my display
>>reads.
>>
>>1  =(0.00): 1.Kh1
>>2 -+(-#10): 1.Kf1
>>3 -+(-#10): 1.Kf2
>>
>>The last piece was taken on black's 87th move.
>>
>>Why did it not play the correct 1. Kh1.
>>is it to do with tablebase depth? or cache?
>>
>>
>>Sarah.
>
>If I tell Gambittiger not to use tablebases under Junior7 interface then
>I get the following analysis at fixed depth 3,4
>
>
>Gambit Tiger 2.0 - Blass,U
>8/8/8/4b3/7k/7p/8/6K1 w - - 0 1
>
>Analysis by Gambit Tiger 2.0:
>
>1.Kf2 Bd4+ 2.Kf1 Bf2 3.Kxf2
>  ³  (-0.63)   Depth: 3   00:00:00
>
>(Blass, Tel-aviv 28.10.2001)
>
>
>Gambit Tiger 2.0 - Blass,U
>8/8/8/4b3/7k/7p/8/6K1 w - - 0 1
>
>Analysis by Gambit Tiger 2.0:
>
>1.Kh1
>  =  (0.00)   Depth: 4   00:00:00, tb=3
>
>(Blass, Tel-aviv 28.10.2001)
>
>You can see from the last analysis that tiger is using tablebases and it is not
>enough to tell the interface not to use tablebases and I need also to tell the
>engine not to use tablebases in the engine parameters
>
>I did it and I got the following information at depth 4
>
>Chess Tiger 14.0 - Blass,U
>8/8/8/4b3/7k/7p/8/6K1 w - - 0 1
>
>Analysis by Chess Tiger 14.0:
>
>1.Kh1 Bh2 2.Kxh2 Kg4
>  ³  (-0.63)   Depth: 4   00:00:00  1kN
>
>(Blass, Tel-aviv 28.10.2001)
>
>
>It seems that tiger needs depth 4 to find Kh1 if you do not tell the interface
>to use tablebases.
>
>Unfortunately tiger probably could get only depth 3 thanks to serious time
>trouble so it could not find Kh1.
>
>Uri

A general problem using engines with Chessbase's GUI is that it's difficult to
prevent them using the tablebases (except by moving or deleting them).
Tablebases are used in two ways.

1) When only the 3/4/5 pieces are on the board the chosen engine is disabled,
and Chessbase's "tablebase engine" picks the moves directly.

2) When more pieces are on the board, the chosen engine "probes" the tablebases
in positions where a piece is captured.

The option "Use Tablebases" in the "Load Engine" menu only stops the first use
of tablebases. The second can be turned off in the engine parameters of SOME
engines. I've tried to set up an engine tournament where some engines were using
tablebases, others not, but I had to give it up as a futile task.

Mike :)



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