Author: Heiner Marxen
Date: 09:17:33 05/31/02
Go up one level in this thread
On May 31, 2002 at 09:52:58, Uri Blass wrote: >On May 31, 2002 at 09:44:41, Les Fernandez wrote: > >>On May 31, 2002 at 07:05:46, Heiner Marxen wrote: >> >>>On May 31, 2002 at 02:44:52, Les Fernandez wrote: >>> >>>>I am interested in having someone with descent hardware and perhaps the 5 piece >>>>egtb run these 6 positions and check them for mates. I think the mate should be >>>>around 8. I am interested in seeing the ce value, ply depth and the time it >>>>took to find it. Thanks. >>>> >>>>rnb2r1k/3q4/2p1p1Q1/pp2NpP1/3P4/b2B2P1/1PPBK3/R7 b - - >>>>rnb2r1k/8/2p1p1Q1/pp2NpP1/3P4/b2B2P1/1PPBK3/R6q b - - >>>>rnb2r1k/8/2p1p1Q1/pp2NpP1/3P4/b2B2P1/qPPBK3/R7 b - - >>>>r7/1ppbk3/B2b2p1/3p4/PP2nPp1/2P1P1q1/3Q4/RNB2R1K w - - >>>>r6Q/1ppbk3/B2b2p1/3p4/PP2nPp1/2P1P1q1/8/RNB2R1K w - - >>>>r7/Qppbk3/B2b2p1/3p4/PP2nPp1/2P1P1q1/8/RNB2R1K w - - >>> >>>According to Chest none of the above contains a (forced) mate in 8. >> >>Hi Heiner, >> >>Ok well maybe I did not make myself clear but I believe the mate will be less >>then 8, in fact may be closer to 4. I do not have the exact number in fact I am >>not even sure it exists but I think it does. >> >>Thanks >> >>Les > > >Chest checks for shortest mate first so if Heiner say there is not mate in 8 >that it means that there is also no shorter mate. > >I also believe that the only mate that may be in the positions that you post may >be mate against the side to move and not mate for the side to move. > >The side to move is not the attacker in the position that you posted. I also realized that, and therefore made an EPD batch from it, so that Chest tries it both ways: first a normal mate with depth 9 (quickly refuted), and then after all legal moves, again a normal mate in 8, this time for the other side to mate. If all legal moves are followed by such a mate in at most 8, Chest states a "lost" position (this can be coded in EPD). Chest didn't find any direct mate of depth 9, and also did not verify any position as "lost since followed by mate in 8". Cheers, Heiner >I am not sure that the side to move is losing but if the side to move is winning >then it is a long game. > >Uri
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