Author: Enrique Irazoqui
Date: 10:23:43 02/02/01
Go up one level in this thread
On February 02, 2001 at 12:58:53, Heiner Marxen wrote: >On February 02, 2001 at 08:40:06, Enrique Irazoqui wrote: > >>On February 02, 2001 at 07:47:52, Heiner Marxen wrote: >> >>>On February 01, 2001 at 17:47:23, Ignacio Santos Crespo wrote: >>> >>>>On January 31, 2001 at 11:25:25, Enrique Irazoqui wrote: >>>> >>>>>On January 31, 2001 at 10:25:50, Heiner Marxen wrote: >>>>> >>>>>>On January 30, 2001 at 17:15:45, Olaf Jenkner wrote: >>>>>> >>>>>>>Perhaps I had in mind this problem what is easily to prove that there is >>>>>>>no shorter mate. >>>>>>> >>>>>>>Pervakow/Sum. #46 >>>>>>>2N5/p4P2/p4RqP/P2krb2/5RNK/2PPBnP1/3P1pP1/5Q2 w - - 1 0 >>>>>> >>>>>>Yes, that can be. Much to my own surprise Chest really proves this >>>>>>as a mate in 46 moves, and needs just 8.2 seconds (K7/600) for it. >>>>>>It gives the following PV: >>>>>> >>>>>> 1. gxf3 Qh5+ >>>>>> 2. Kxh5 Bg6+ >>>>>> 3. Kxg6 Rg5+ >>>>>> 4. Kh7 Rg7+ >>>>>> 5. Kh8 Rh7+ >>>>>> 6. Kg8 Rh8+ >>>>>> 7. Kg7 Rh7+ >>>>>> 8. Kf8 Rh8+ >>>>>> 9. Ke7 Re8+ >>>>>>10. Kd7 Rd8+ >>>>>>11. Kc7 Rd7+ >>>>>>12. Kb8 Rb7+ >>>>>>13. Ka8 Rb8+ >>>>>>14. Kxa7 Rb7+ >>>>>>15. Kxa6 Ra7+ >>>>>>16. Kb5 Rxa5+ >>>>>>17. Kb4 Rb5+ >>>>>>18. Ka3 Rb3+ >>>>>>19. Ka2 Rb2+ >>>>>>20. Ka1 Ra2+ >>>>>>21. Kb1 Rb2+ >>>>>>22. Kc1 Rb1+ >>>>>>23. Kc2 Rb2+ >>>>>>24. Kd1 Rb1+ >>>>>>25. Ke2 Re1+ >>>>>>26. Kxf2 Re2+ >>>>>>27. Kg1 Rg2+ >>>>>>28. Kh1 Rg1+ >>>>>>29. Kh2 Rh1+ >>>>>>30. Kg2 Rg1+ >>>>>>31. Kh3 Rxg3+ >>>>>>32. Kh4 Rh3+ >>>>>>33. Kg5 Rh5+ >>>>>>34. Kg6 Rg5+ >>>>>>35. Kh7 Rg7+ >>>>>>36. Kh8 Rh7+ >>>>>>37. Kg8 Rh8+ >>>>>>38. Kg7 Rh7+ >>>>>>39. Kg6 Rg7+ >>>>>>40. Kh5 Rg5+ >>>>>>41. Kh4 Rh5+ >>>>>>42. Kg3 Rh3+ >>>>>>43. Kf2 Rxf3+ >>>>>>44. Ke2 Rf2+ >>>>>>45. Nxf2 Ke5 >>>>>>46. R4f5# >>>>>> >>>>>>I even had to increase the maximal allowed depth in Chest (formerly 30). >>>>>>Quite an exceptional position! >>>>>> >>>>>>Can the playing programs solve this, also? I suspect so. >>>>> >>>>>92 plies? You must be kidding. They pick gxf3 instantly with a huge score, but >>>>>no mate. I only tried Deep Fritz, Gambit Tiger and Shredder 5, but I don't think >>>>>any playing program will see it. >>>>> >>>>>Enrique >>>>> >>>>>>Heiner >>>> >>>>On my Pentium 166 after 2... Bg6+, Junior 6 (with 15 Mb. hash) say mate in 42 >>>>(6´2") >>> >>>While I'm pleased to hear that a program solved this one, from the above >>>I believe "mate in 44" would be correct, not "mate in 42". Can you show >>>us a PV? I would like to check it. Someone errs, and I'd like to know who. >>> >>>Heiner >> >>Junior 6 says mate in 42 after 2... Bg6+ in 55 seconds on a P750, 128MB hash, >>see below. I find very impressive that a playing program can see so far ahead >>and so quickly. I'm trying from the initial position with Deep Junior, but after >>14 hours it doesn't see the mate yet. > >Hmm, maybe because there are some #7 side variants? E.g. after 1.gxf3 >Qxf6+ Nxf6+ Kc6 Rc4+ Kb7 Nd6+ =*= f8=Q+ Re8 Qxe8+ Bc8 Qxc8# Maybe. I gave up after 18 hours. >>Enrique >> >>[D]2N5/p4P2/p4RbP/P2kr2K/5RN1/2PPBPP1/3P1p2/5Q2 w - - 0 1 >> >>Analysis by Junior 6.0: >[snip] >>3.Kxg6! Rg5+ 4.Kh7 Rg7+ 5.Kh8 Rh7+ 6.Kg8 Rh8+ 7.Kg7 Rh7+ 8.Kf8 Rh8+ 9.Ke7 Re8+ >>10.Kd7 Rd8+ 11.Kc7 Rd7+ 12.Kb8 >> +- (#42) Depth: 44 00:00:55 40825kN >> >>(Irazoqui, Cadaqués 02.02.2001) > >The above line follows exactly my PV from above. Unfortunately Juniors PV >is not complete, so I cannot investigate this further. But when Chest is >right with #46, then Junior should have said #44 (or larger), but not #42. >That would be a bug, wouldn't it? > >OTOH, Chest may have the bug, which is what worries me a bit. >Would you mind to provide the complete line up to the mate move? >You could play it out after the above analysis. Thanks in advance! Sorry, I can't right now. Maybe in a few days I'll have the time to try. Enrique >BTW, I spent some 5 minutes for Crafty analysis, but it appears to not solve >it: it did reach depth 14, only. > >Heiner
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