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Subject: Re: Tablebases question

Author: Tony Werten

Date: 08:45:41 04/27/01

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On April 27, 2001 at 11:14:04, Tony Werten wrote:

>On April 27, 2001 at 10:40:58, James T. Walker wrote:
>
>>This position was reached DF/DJ the other day.  The behavior of Deep Fritz is
>>not unusual for programs with tablebases.  That is trying to give away a piece
>>to reach the won ending in tablebases.  My question is,  why do these programs
>>think that the piece will be taken?  Why would taking the piece be in the PV
>>when it is obvious that taking it leads to mate and it is not the best move?  If
>>it is not expected to capture the piece then what would be the point of the
>>move?  I'm not talking about later when taking the piece was done because it
>>leads to a longer mate than not taking the piece.  Programmers? Anyone?
>
>I have the following pv
>6/11 99,865 3s 41Kn/s 1.Rc6 Kb4 2.Rb3+ Ka4 3.Ra6+ Rxa6
>
>This means it's a checkmate in 135 ply. If black doesn't take the rook he looses
>even faster.

At ply 9 it changes to Rc6 Kxc6 cm in 127(meaning Kb4 leads to a faster mate)
ply 10: Rc3 Kd4 Kf4 Kxc3  cm in 125 ply
ply 10:  g4 Kc4 Rc6 Kxd3 cm in 121 ply

I'll let it run for a while to see if it comes up with something shorter.

>
>Tony
>
>>
>>[D]r7/8/5R2/2k5/8/3R1K2/6P1/8 w - - 0 70
>>
>>Thanks,
>>Jim



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