Author: Uri Blass
Date: 08:49:53 12/03/04
Go up one level in this thread
On December 03, 2004 at 11:31:36, Tony Nichols wrote: >On December 02, 2004 at 03:53:14, Mike Hood wrote: > >>On December 01, 2004 at 15:52:03, Tony Nichols wrote: >> >>>On December 01, 2004 at 15:31:34, John Merlino wrote: >>> >>>>On December 01, 2004 at 14:42:06, Tony Nichols wrote: >>>> >>>>>On December 01, 2004 at 14:28:44, John Merlino wrote: >>>>> >>>>>>On December 01, 2004 at 14:06:54, Tony Nichols wrote: >>>>>> >>>>>>>On December 01, 2004 at 13:16:06, Dann Corbit wrote: >>>>>>> >>>>>>>>On December 01, 2004 at 10:13:56, Tony Nichols wrote: >>>>>>>> >>>>>>>>>I was looking at a study in chessbase 8 that is a mate in three. Unable to solve >>>>>>>>>it myself I fired up Shredder 8. To my surprise Shredder claimed it was a mate >>>>>>>>>in 5!? Deep Fritz 8 also said mate in 5. When I played the key move both engines >>>>>>>>>saw the mate in 2! Other engines found the mate in 3 immediately(Hiarcs 9, Chess >>>>>>>>>Tiger 15, Gambit Tiger 2.0, Crafty 19.17 etc.). If someone would tell me how to >>>>>>>>>post the position I will. Has anyone else had similiar problems? >>>>>>>> >>>>>>>>What is the position you are looking at? >>>>>>>Hi Dan >>>>>>>I don't know how to post the position. If you tell me how I will post it. >>>>>>>Regards >>>>>>>Tony >>>>>>>P.S. it is a study by Milan Vukcevich >>>>>> >>>>>>You can just describe the position (which pieces are on which squares, and whose >>>>>>side to move it is) and somebody else can convert it to the proper format. >>>>>> >>>>>>Or, if you know how to convert the position into a FEN string, just put a line >>>>>>in your post that has a [D] at the beginning and then paste the FEN string >>>>>>immediately after it. That will do the trick. >>>>>> >>>>>>jm >>>>>ok here goes [D]3K1B2/2pPPp2/7R/2k2r2/7q/P2Q4/8/8 w - - 0 1 >>>>>wKd8,Qd3,Bf8,Rh6,Pa3,d7,e7/bKc5,Qh4,Rf5,Pc7,f7 >>>> >>>>CM9000 also finds it in a handful of milliseconds. It is possible, since some >>>>solution paths require underpromotions (e.g. 1.Ra6 Qc4 2.e8=N+! Kb5 3.Nxc7#), >>>>that this could be the reason that some engines don't find the mate in 3. >>>> >>>>jm >>> >>> Interestingly enough all my UCI engines find it immediately in Frtiz 8 GUI. >>>Only native chessbase engines have a problem. >>>Regards Tony >> >>Tony, you can't generalize by saying native engines don't find the mate in 3. As >>you can see below, Shredder 8 and Junior 8 don't find the mate in 3, but Fritz >>8, Hiarcs 9 and Tiger 15 do find the mate. It's a common "fault" that Fritz, >>Shredder and Junior stop searching for a shorter mate when they've already found >>an unavoidable longer mate (although Fritz succeeds in your example). Tiger 15 >>doesn't have this "fault", because it keeps on searching after it's already >>found a mate. >> >>================================== >> >>Analysis by Shredder 8: >> >>1.Rxh4 >> +- (15.33) Depth: 1/1 00:00:00 >>1.Rxh4 >> +- (27.18) Depth: 1/1 00:00:00 >>1.Rxh4 >> +- (27.18) Depth: 1/1 00:00:00 >>1.Rxh4 Rd5 >> +- (27.45) Depth: 2/4 00:00:00 >>1.Rxh4 Rf6 >> +- (28.09) Depth: 2/4 00:00:00 >>1.Rxh4 Kb6 2.e8Q >> +- (29.03) Depth: 2/8 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 >> +- (39.48) Depth: 2/8 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 >> +- (39.48) Depth: 2/8 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.e8Q >> +- (39.59) Depth: 3/6 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.e8Q c6 >> +- (39.85) Depth: 4/8 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q c6 >> +- (40.12) Depth: 4/14 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q c6 4.Qb1 >> +- (40.38) Depth: 5/8 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.Qb1+ Kc3 4.e8Q c6 >> +- (40.88) Depth: 5/9 00:00:00 >>1.Qxf5+ Kc4 2.Kxc7 >> +- (40.88) Depth: 5/18 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q Kb3 4.Kxc7 f6 >> +- (41.13) Depth: 6/10 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q Kb2 4.Kxc7 Kb3 >> +- (41.63) Depth: 6/10 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 5.Qf1# >> +- (#150) Depth: 6/18 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 5.Qf1# >> +- (#5) Depth: 7/12 00:00:00 16kN >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 5.Qf1# >> +- (#5) Depth: 8/12 00:00:00 21kN >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 5.Qf1# >> +- (#5) Depth: 9/12 00:00:00 31kN >> >>========================================= >> >>Analysis by Fritz 8: >> >>1.Qxf5+ Kd4 2.Rxh4+ Kc3 3.Qf3+ >> +- (#6) Depth: 5/24 00:00:02 1669kN >>1.Ra6! >> +- (#5) Depth: 5/24 00:00:02 1740kN >>1.Ra6 Qg3 2.e8Q+ Qd6 3.Qee3# >> +- (#3) Depth: 5/24 00:00:02 1757kN >>1.Ra6 Qg3 2.e8Q+ Qd6 3.Qee3# >> +- (#3) Depth: 5/24 00:00:02 1760kN >> >>=========================================== >> >>Analysis by Hiarcs 9: >> >>1.Rxh4 Rd5 2.e8Q+ Kc6 >> +- (27.16) Depth: 1/10 00:00:00 >>1.Qxf5+ >> +- (31.50) Depth: 1/10 00:00:00 >>1.Qxf5+ Kd4 >> +- (31.50) Depth: 1/10 00:00:00 >>1.Qxf5+ Kd4 >> +- (35.95) Depth: 2/10 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 >> +- (35.95) Depth: 2/10 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 >> +- (36.24) Depth: 3/11 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Bg7+ Kd2 4.Qf2+ Kd3 5.e8Q c6 >> +- (37.74) Depth: 3/15 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Bg7+ Kd2 4.Qf2+ Kd3 5.e8Q c6 >> +- (38.28) Depth: 4/16 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Bg7+ Kd2 4.Qf2+ Kd3 5.e8Q c6 >> +- (#7) Depth: 4/16 00:00:00 >>1.Qxf5+ Kd4 2.Rxh4+ Kc3 3.Qf3+ Kc2 4.Rh2+ Kc1 >> +- (#5) Depth: 4/17 00:00:00 >>1.Qxf5+ Kd4 2.Rxh4+ Kc3 3.Qf3+ Kc2 >> +- (#5) Depth: 5/19 00:00:00 56kN >>1.Ra6 Qe1 >> +- (#4) Depth: 5/19 00:00:00 65kN >>1.Ra6 Rd5 2.Ra5+ Kc6 3.Qa6# >> +- (#3) Depth: 5/19 00:00:00 77kN >> >>========================================= >> >>Analysis by Junior 8: >> >>1.a4 Rd5 2.Rxh4 >> +- (10.78) Depth: 3 00:00:00 >>1.Bg7 Qf4 2.Qc3+ Kb5 3.e8Q >> +- (16.89) Depth: 3 00:00:00 1kN >>1.Rxh4 Kb6 2.e8Q >> +- (26.82) Depth: 3 00:00:00 5kN >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.Qd3+ Ka2 4.Qc4+ Kxa3 5.e8Q+ >> +- (31.87) Depth: 3 00:00:00 12kN >>1.Qxf5+! >> +- (32.17) Depth: 6 00:00:00 15kN >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.e8Q f6 4.Qb1+ Kc3 5.Qee1# >> +- (#5) Depth: 6 00:00:00 163kN >>1.Qxf5+ Kc4 2.Rxh4+ Kb3 3.e8Q f6 4.Qb1+ Kc3 5.Qee1# >> +- (#5) Depth: 6 00:00:00 215kN >> >>======================================= >> >>Analysis by Chess Tiger 15.0: >> >>1.Qxf5+ >> +- (14.56) Depth: 1 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q >> +- (44.04) Depth: 1 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q >> +- (44.04) Depth: 1 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.e8Q >> +- (44.04) Depth: 2 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qc5+ Kb2 4.e8Q >> +- (44.48) Depth: 3 00:00:00 >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ >> +- (45.38) Depth: 4 00:00:00 3kN >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 >> +- (#5) Depth: 4 00:00:00 4kN >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 >> +- (#5) Depth: 5 00:00:00 10kN >>1.Qxf5+ Kc4 2.Rxh4+ Kc3 3.Qf3+ Kb2 4.Rh2+ Ka1 5.Qf1# >> +- (#5) Depth: 6 00:00:00 22kN >>1.Ra6 Qg5 2.Ra5+ Kb6 3.Qa6# >> +- (#3) Depth: 6 00:00:00 55kN > >Hi Mike > >I wasn't saying that all CB native engines have this problem,But all engines >that have this problem are CB native. >Regards >Tony There are probably a lot of non chessbase native engine that stop to search after finding the first mate and do not look for the shortest mate so I am almost sure that it is possible to find non native chessbase engine with the same problem. Movei find mate in 3 in the relevant position but it is only luck and you will probably be able to find position when it fails to find the shortest mate because it stops searching more iterations after finding a mate score. Uri
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