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Subject: Re: Mate in 46

Author: Enrique Irazoqui

Date: 05:40:06 02/02/01

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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
>>>>>[D]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.

Enrique

2N5/p4P2/p4RbP/P2kr2K/5RN1/2PPBPP1/3P1p2/5Q2 w - - 0 1

Analysis by Junior 6.0:

3.Kxg6 Rg5+
  +-  (34.96)   Depth: 3   00:00:00
3.Kxg6 Rg5+
  +-  (34.96)   Depth: 6   00:00:00
3.Kxg6 Rg5+
  +-  (34.96)   Depth: 9   00:00:00  2kN
3.Kxg6 Rg5+
  +-  (34.96)   Depth: 12   00:00:00  5kN
3.Kxg6!
  +-  (35.26)   Depth: 15   00:00:00  20kN
3.Kxg6!
  +-  (35.56)   Depth: 18   00:00:00  71kN
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
  +-  (27.69)   Depth: 21   00:00:00  211kN
3.Kxg6!
  +-  (27.99)   Depth: 24   00:00:00  296kN
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
  +-  (32.02)   Depth: 24   00:00:00  392kN
3.Kxg6!
  +-  (32.32)   Depth: 27   00:00:01  790kN
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
  +-  (32.32)   Depth: 30   00:00:02  1089kN
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
  +-  (24.40)   Depth: 33   00:00:03  2227kN
3.Kxg6!
  +-  (24.70)   Depth: 36   00:00:04  2379kN
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
  +-  (25.16)   Depth: 36   00:00:04  2608kN
3.Kxg6!
  +-  (25.46)   Depth: 38   00:00:05  2897kN
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
  +-  (28.35)   Depth: 38   00:00:06  3153kN
3.Kxg6!
  +-  (28.65)   Depth: 40   00:00:08  4369kN
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
  +-  (32.74)   Depth: 40   00:00:11  6960kN
3.Kxg6!
  +-  (33.04)   Depth: 42   00:00:16  9629kN
3.Kxg6!
  +-  (33.34)   Depth: 44   00:00:23  14185kN
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
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)



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