Author: Robert Hyatt
Date: 09:43:51 10/13/98
Go up one level in this thread
On October 13, 1998 at 11:23:41, blass uri wrote: > >On October 13, 1998 at 07:34:46, Bernhard Bauer wrote: > >>On October 13, 1998 at 06:05:55, blass uri wrote: >> >>> >>>On October 13, 1998 at 05:54:00, blass uri wrote: >>> >>>> >>>>On October 13, 1998 at 04:34:00, Amir Ban wrote: >>>> >>>>>On October 13, 1998 at 02:12:24, Jouni Uski wrote: >>>>> >>>>>>In SSDF game archive there is 5834 games. In 21 games there is KQ-KR ending. >>>>>>And 20 of these were won by Q side WITHOUT any use of TBs! Quite surprising - >>>>>>isn't this normally considered as difficult ending? >>>>> >>>>>I've never seen this ending in a computer-computer game where the side with the >>>>>queen failed to win, at any time control. >>>>> >>>>>This endgame is quite easy for a computer. >>>> >>>>Is it easy when the defendor use tablebases? >>>> >>>>I found that the defendor without tablebases(when the defendor is a computer >>>>program) may miss a simple draw by perpetual check in positions when there is >>>>black queen at f2 and white king at h1. >>> >>>Here is an example >>> >>>7R/8/8/8/8/k7/5q2/7K white to move and draw >>>Fritz5(without tablebases) plays Rg8 and Junior5(16 bit) Rh3+ >>>when Ra8+ is the only way to draw. >>> >>>Uri >>> >> >>Crafty 15.20 finds the draw without tablebases. >>On a 2xPPro 233MHz crafty sees Ra8+ at ply 14 in 2:48 min. >>Crafty sees the draw (score =-0.66) at ply 23 in 3:45 min. >>The output for ply 42 is: >> 42-> 8:04 -0.66 1. Ra8+ Kb3 2. Rb8+ Kc3 3. Rc8+ Kd3 >> 4. Rd8+ Ke3 5. Re8+ Kd4 6. Rd8+ Ke4 >> 7. Re8+ Kd5 8. Rd8+ Kc4 9. Rc8+ Kb4 >> 10. Rb8+ Ka4 11. Ra8+ Kb5 12. Rb8+ >> Ka5 13. Ra8+ Kb6 14. Rb8+ Kc5 15. Rc8+ >> Kd6 16. Rd8+ Kc6 17. Rc8+ Kd7 18. Rd8+ >> Ke6 19. Re8+ Kd5 >>Kind regards >>Bernhard > > >You need to search at least 54 plies forward to see the stalemate or repetition >and many programs cannot search more than 50 plies. > >I think that most of the top programs cannot search to 42 plies in this position >even in 8000 minutes. >I think that crafty is more than 1000 times faster than most of the top programs >in finding the draw. > >Uri Personally, I don't consider this a good thing, anyway, and am working to "tone down" those extensions that lets it see the above, because it certainly hurts at times to be out at 40 plies searching... > >> >> >>> >>>> >>>>Uri >>>>> >>>>>Amir
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