Author: Paul
Date: 11:54:03 10/09/01
Go up one level in this thread
On October 09, 2001 at 14:27:10, Uri Blass wrote: >On October 09, 2001 at 14:21:18, Angrim wrote: > >>On October 09, 2001 at 13:01:13, Uri Blass wrote: >> >>>[D]8/1P6/8/5k2/2K4p/7r/1r4p1/6R1 b - - 0 61 >>> >>>This position is from the game Tao-Deep Junior7 in the last WMCCC >>> >>>Chest need some hours on p200 to see mate in 10(I used chest by the way that was >>>explained by paul some days ago >>> >>>see http://www.icdchess.com/forums/1/message.shtml?191857 >>> >>>Solution:61...Rg3 62.Kd4 h3 63.Kd5 h2 64.b8Q Rxb8 65.Re1 Rd3+ 66.Kc4 h1Q 67.Re5+ >>>Kxe5 68.Kxd3 Qd1+ 69.Kc3 Rb3+ 70.Kc4 Qc2# >>> >>>15961 seconds,292,407,791 nodes >>> >>>In the game Deep Junior7 missed the right move(Rg3) but it did not help Tao that >>>resigned after Rxb7. >>> >>>How much time does your program need to see mate in 10 with the full 5 piece >>>tablebases and without tablebases? >>> >>>Uri >> >>Well, I don't have tablebases for standard chess, so just results >>without tables. This is the sort of mate that pn^2 search has the >>most trouble with, since not only are the winning moves not forcing >>moves, but there are lots and LOTS of forcing moves that don't win. >>It will work out every possible series of pointless checks before it >>thinks even 3 ply deep down a non-forcing line like Rg3.. after >>about 1/2 hour it is working on lines that have a single non-forcing >>move in them, and usually a huge series of forcing moves. >> >>On the other hand, my minmax searcher(which has piece values + mobility only) >>found the right move at ply 2 and never changed its mind. >>Guess Junior was too smart for its own good in that position. >> >>Angrim > >I suspect that Junior used tablebases and it saw another mate by tablebases. > >Capturing may be the faster way to get a tablebase mate. > >Uri Yes, I suspect so ... mine sees a mate in 28 in 8 seconds with tablebases, a number that drops later. But without tbs it takes minutes to see the mate in 10, mine gives a different line: Rg3 Kc5 h3 b8=Q Rxb8 Kd6 h2 Ra1 g1=Q Ra5+ Kf6 Ra6 Rb6+ Rxb6 Qxb6+ Kd7 Rd3+ Kc8 Rd8# Paul
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