Author: Enrique Irazoqui
Date: 16:24:40 02/02/01
Go up one level in this thread
On February 02, 2001 at 19:08:38, Tony Werten wrote: >On February 02, 2001 at 12:10:58, James T. Walker wrote: > >>On February 02, 2001 at 03:19:14, Timothy J. Frohlick wrote: >> >>>On February 02, 2001 at 01:28:59, Jouni Uski wrote: >>> >>>>[D]8/6kn/3B3p/5K1B/8/8/8/8 b - - >>>> >>>>resign 1-0! Why? Is this really white's win? >>>> >>>>JouniDate: 1/2/2001 >>> >>>Jouni, >>> >>>Gambit Tiger without tablebases solves this as a mate in 46 in 26 minutes on a >>>PII 333 with 48 Megs Hash. >>> >>>1... Ng5 2. Bc5 Nf7 3. Bd4+ Kf8 4. Kf6 Ng5 5. Bc5+ Kg8 6. Kf5 Nf7 7. Be7 Ng5 8. >>>Bb4 Nf7 9. Kg6 Ne5+ 10. Kf6 Nd7+ 11. Ke7 Ne5 12. Bc3 Nc6+ 13. Ke8 Kh7 14. Kf7 >>>Ne5+ 15. Kf6 Nc6 16. Bf3 Nd8 17. Bb4 h5 18. Be4+ Kh8 19. Be7 Nc6 20. Bxc6 Kh7 >>>21. Be4+ Kg8 22. Kg6 Kh8 23. Bd5 h4 24. Bf6# >>> >>> >>>1-0 >>> >>>Maybe tablebases are not all that great after all. They don't always find the >>>shortest solution to a problem. >>> >>>Tim Frohlick >> >>Why mate in 46 and then you give a mate in 24 line? I believe the "mate in 46" >>is true as Shredder 5 finds a mate in 47 (maybe a difference in terms) but where >>did the above line which is 24 moves come from? > >Normally a move consists of 2 ply, but in this case the first and the last move >are only 1 ply. So effectively 23 moves => 46 ply. > >47 ply is impossible since black starts and white finishes so it has to be even. Not really. In the line posted above, after 24.Bf6# the program must see 1 more ply to realize that the black KIng has no escape, so it's a 47 ply search. A typical problem "white to play and mate in 6" is 12 ply deep, not 11. Enrique >Tony > >>Jim
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