Author: blass uri
Date: 11:06:29 03/14/99
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On March 14, 1999 at 12:18:28, Robert Hyatt wrote: >On March 14, 1999 at 10:24:26, blass uri wrote: > >>R4b1q/5Pp1/Pk4Pp/3K3P/7P/8/8/8 w - - 0 1 >> >>white wins by 1.a7 >>Genius3 finds it in less than 1 second >> >>unfortunately some engines for Fritz5 cannot solve it(crafty16.5's move is Ke6 >>and the evaluation is 0.00 at depth 19,exchess2.51's move is Ke6 and the >>evaluation is 0.00 at depth 14 ) >> >>I understand that after 1.a7 Kb7 2.Re8 Kxa7 3.Kc6 white has no threat. >> >>Is it the reason that these engines cannot solve it? >> >>Do they use null move with an infinite R so they do not analyze at all even to >>reduced depth moves with no threat? >> >>Fritz5(16 bit) surprises and solves this position but only at depth 14. >>The move is Ke6 at the beginning of iteration 14 with the strange evaluation >>-0.47. >> >>Suddenly fritz5(16 bit) sees Kc4 with evaluation -0.44. >>The evaluation jumps to 8.xx >> >>Kc4 is winning and fritz saw winning evaluation so I can say that Fritz can >>solve it. >> >>Fritz5(16 bit) at depth 15 changes its mind to the simpler winning move 1.a7 >> >>Junior5 has no problem to solve the position because it is not a null mover. >> >>Uri > > >this is simply one of the many null-move killer positions. Nothing much to do >about it either... > >However, for every one of these that comes up, I've seen 10 where a >non-null-mover can't get deep enough to solve the position. The differnece is that non-null movers can get deep enough to solve the position if they had more time and null movers cannot solve some positions and it is not a problem of time. I think that it is better to analyze moves with no threat to reduced depth so you do not use more than 1% of your time for analyzing moves with no threat. Uri
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