Author: Uri Blass
Date: 08:17:31 09/15/00
Go up one level in this thread
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
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