Author: Robert Hyatt
Date: 09:20:24 09/15/00
Go up one level in this thread
On September 15, 2000 at 11:17:31, Uri Blass wrote: >On September 15, 2000 at 11:01:58, Robert Hyatt wrote: > >>On September 15, 2000 at 10:47:47, Uri Blass wrote: >> >>>On September 15, 2000 at 10:43:06, Robert Hyatt wrote: >>> >>>>On September 15, 2000 at 10:34:53, Uri Blass wrote: >>>> >>>>>On September 15, 2000 at 10:20:57, Helmut Conrady wrote: >>>>> >>>>>>On September 15, 2000 at 09:01:22, Andreas Stabel wrote: >>>>>> >>>>>>>On September 15, 2000 at 08:43:27, Bernhard Bauer wrote: >>>>>>> >>>>>>>>On September 15, 2000 at 08:18:59, Helmut Conrady wrote: >>>>>>>> >>>>>>>>>Im wondering, what is the deepest chessproblem ever composed. There is a problem >>>>>>>>>created by Petrovic in 1969 which might lead to a mate in 270. >>>>>>>>> >>>>>>>>>[D]8/Bk3p1p/1P3p2/KP2n2p/1P1p4/1Pp2p2/B1P5/7B w - - 0 1 >>>>>>>>> >>>>>>>>>Unfortunately I haven t got the solution. >>>>>>>>> >>>>>>>>>Can onyone explain how to win this. >>>>>>>>>Does anyone know a deeper problem? >>>>>>>>> >>>>>>>>>Thanks in advance. >>>>>>>>> >>>>>>>>>Helmut >>>>>>>> >>>>>>>>Found an old posting. >>>>>>>>----------------------------------------------------------------- >>>>>>>>The task record for a legal position is this one: >>>>>>>> >>>>>>>>Petrovici, "Problem", 1969 >>>>>>>>White: Ka5, Ba2, Ba7, Bh1, pb3, pb4, pb5, pb6, pc2 (9) >>>>>>>>Black: Kb7, Ne5, pc3, pd4, pf3, pf6, pf7, ph5, ph7 (9) >>>>>>>>#270 >>>>>>>> >>>>>>>>Solution: >>>>>>>> >>>>>>>>1.Bb1 h4 2.Ka4 Ka8 >>>>>>>>(Black's king oscillates to and from b7 except when a black >>>>>>>>pawn is moved) >>>>>>>>3.Ka3 4.Ka2 5.Ka1 6.Ba2 7.Kb1 8.Kc1 9.Kd1 10.Ke1 11.Bb1 >>>>>>>>12.Kf1 (White begins a triangulation in order to lose the move) >>>>>>>>13.Kf2 14.Ke1 15.Kd1 15.Kc1 17.Ba2 18.Kb1 19.Ka1 20.Bb1 >>>>>>>>21.Ka2 22.Ka3 23.Ka4 Kb7 24.Ka5 f5 >>>>>>>>(Black moves a pawn rather than permit White's king to be >>>>>>>>moved to a6. White makes nine more triangulations, each time >>>>>>>>forcing Black to move a pawn) >>>>>>>>47...pf4 70...pf6 93...pf5 116...ph3 139...ph2 162...ph6 >>>>>>>>185...ph5 208...ph4 231...ph3, and now >>>>>>>>254.Ka5 Kc8 255.Ka6 f2 256.b7+ Kd7 257 b8=Q f1=Q 258.Q:e5 Q:h1 >>>>>>>>259.Qg7+ Ke6 260.Qg6+ Ke5 261.Bb8+ Ke4 262.Qc6+ Ke3 263.Q:h1 Kf2 >>>>>>>>264.B:f4 Ke2 265.b6 d3 266.c:d3 Kf2 267.Bc2 Ke2 268.Bd1+ Kf2 >>>>>>>>269.Qf3+ Kg1 270.Be3 mate. >>>>>>>> >>>>>>>>Cornel Pacurar >>>>>>>>http://www.orbonline.net/~corpac/index.html >>>>>>>>---------------------------------------------------------------------- >>>>>>>>Kind regards >>>>>>>>Bernhard >>>>>>> >>>>>>>I don't think this solution is correct. Black has to move some pawns during >>>>>>>the first white king tour or the white king will escape to g3 or h3 and >>>>>>>start munching black pawns and win that way. To stop this black has to do >>>>>>>the following pawn moves h4-h3-h2 and f5-f4. This will cause the mate to >>>>>>>be a lot less than 270, but still awesome. >>>>>> >>>>>>I think the 270 moves must be correct, because this problem was discussed in the >>>>>>problem magazine "Die Schwalbe" 8/2000. The discussion was: 270 or 271 moves to >>>>>>mate. :) >>>>>> >>>>>> >>>>>>Helmut >>>>> >>>>>This is not convincing because you need to prove that there is no shorter mate. >>>>>The problem seem to be not a good problem also because the solution is not >>>>>unique and white can win by 1.Ka4 instead of 1.Bb1 >>>>> >>>>>Uri >>>> >>>> >>>>I think the point is that if not Bb1, then c3 gives white a headache. With the >>>>bithop at b1, c3 simply drops the pawn. >>> >>>You are right. >>>It should be d3. >>> >>>After Ka4 d3 I see that white cannot prevent a new black queen. >>> >>>Uri >> >>Right. I was changing c3 to d3 when the phone rang. By the time I got off >>the phone, you had already found it. :) >> >>This is one of several types of problems we used to tackle with Cray Blitz. >> >>We solved this one perfectly, but we obviously couldn't see the mate. The >>problem a computer might have here is that as the king makes the walk, it >>reaches a position where it repeats the position for a second time, and some >>programs might choke there and simply oscillate the king and draw instantly. >>Cray Blitz had a unique approach to accepting draw scores and had no problem >>with this at all. I don't think Crafty will have the problem as it knows >>that near the root, 2-fold repetitions are not draws. > >I think that there is another problem for computers here. > >This is the position after 12 moves. >[D]k7/B4p1p/1P3p2/1P2n3/1P1p3p/1Pp2p2/2P2K2/1B5B w - - 0 1 > >In this position a lot of programs including Crafty(at least at short time >control) will play 13.Bxf3+ that is probably drawing because the white bishop >are useless. > >After 13.Bxf3+ Nxf3 14.Kxf3 f5 white has no way to make progress. > >Uri This is even worse than you think. Crafty has great trouble here and would probably play Bxf3 no matter how long it has. The problem is that this is a null-move killer position after that, as the two split pawns offer many zug positions that break the null-move assumption. CB only used null-move R=1, non-recursively. I just tried it on a pretty slow single cpu machine and it has no problem quickly finding that Bxf3 leads to a 0.00 score due to repetition. But Crafty fails high, fails low, fails all over the place, in this position.
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