Author: Uri Blass
Date: 09:55:11 01/19/01
Go up one level in this thread
On January 19, 2001 at 10:06:18, Dieter Buerssner wrote:
>On January 19, 2001 at 05:15:41, Uri Blass wrote:
>
>[Please refer to the post I am answering for the board display]
>>8/8/p1r5/6k1/KP6/8/8/5R2 b - - 0 1
>>
>>In this position Rebel century3 blundered and played 66...Rb6 when white
>>probably forces mate in 48(The main line is losing a tempo by 67.Rf2 Kg4 68.Rf8
>>Kg5 69.Rf1 when Rebel to mope has to play a move that desroys black's position I
>>did not learn the position to understand exactly why but I believe the main line
>>of chess programs)
>>
>>How much time does your program need to find 66...Rc3 or 66...Rc2 that are
>>probably enough for a draw(I am not sure and I may be wrong about it)?
>>
>>How much time does it need with tablebases and how much time does it need
>>without tablebases?
>
>With TBs (KRPKR + all 4-men) Yace fails low for Rb6 after almost 5 minutes
>on AMD K6-2 475.
>
> nodes time score depth
> 9364951 4:44.8 -0.89 18-- 1...Rb6 2.Rf8 Kg4 3.Rf7 Rg6
> 12247832 5:53.1 -Mat48 18t 1...Rb6 2.Rf8 Kg4 3.Rf7 Kg5 4.Rf1 Kg6 5.Rf4 Rc6
> 6.Ka5 Kg7 7.Rd4 Kf7 8.Rd7+ Ke8 9.Ra7 Rc4
> 10.Rxa6 {EGTB} 10...Kd7! 11.Kb5! Rd4 12.Rb6!
> Re4 13.Rb7+ Kc8! 14.Ka6! Re6+! 15.Ka7! Re3
> 16.b5! Ra3+! 17.Kb6 Rb3 18.Rf7 Rb4 19.Rf8+! Kd7
> 20.Rb8! Rc4 21.Ka7! Rd4 22.b6 Ra4+! 23.Kb7 Rb4!
> 24.Rf8 Rb3 25.Rf2 Rb4 26.Rd2+! Ke6! 27.Kc7
> Rc4+! 28.Kb8! Rb4 29.b7! Rb3 30.Ra2! Kd6 31.Ra7
> Rc3 32.Ka8! Rb3! {Not all positions found in
> TB} {-80}
> 14806072 7:18.4 -Mat49 18t+ 1...Rc3 2.Ra1 Kf6 3.Ka5 Rc6 4.Rh1 Ke7 5.Rh8 Kd7
> 6.Rf8
> 17849754 9:28.6 -0.21 18t 1...Rc3 2.Ra1 Kf6 3.Ka5 Rc6 4.Re1 Kf7 5.Re5 Rh6
> 6.Re4 Rc6 7.Re1 Rh6 8.Re5 Rf6 9.Rc5 Ke7 10.Rc7+
> Kd8 11.Ra7 Rf4 {0}
>
>It also shows a very bad performance, due to the many TB accesses.
>After 1...Rb6 it finds also a shorter mate:
>
> 19213357 8:50.2 Mat44 19t 2.Rf3 Kg4 3.Rf2 Kg5 4.Rf1 Kg6
The game move was 4...Kg4 instead of 4...Kg6 and I guess there should be mate in
at most 41 after 4...Kg4
Your program is fast in finding the mate because I found that Deep Fritz could
not see a forced mate even after an hour in the position after 1...Rb6
It failed high again and again but did not solve the fail high.
Crafty also needs a long time to see the forced mate and I guessed mate in 48
based on the fact that it said mate in 47 against itself after a long time a
move later.
Uri
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