Author: Robert Hyatt
Date: 08:01:58 09/15/00
Go up one level in this thread
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. The other type of problem that caused us a lot of grief were the so-called 'straightjacket' positions. One such idea was to create a position where each side had only one legal move (obviously a check, counter-check, etc...) for as many consecutive moves as possible, followed by an absolutely air-tight forced mate. We could get to 60 plies almost instantly and could blow array subscripts if we weren't careful. I didn't think much of using the program to solve problems, but it did expose some potential serious bugs...
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