Author: blass uri
Date: 08:49:54 11/22/98
Go up one level in this thread
On November 22, 1998 at 10:44:54, Robert Hyatt wrote: >On November 22, 1998 at 02:31:47, blass uri wrote: > >> >>On November 21, 1998 at 19:12:59, Robert Hyatt wrote: >> >>>On November 21, 1998 at 15:55:11, blass uri wrote: >>> >>>> >>>>On November 21, 1998 at 13:36:46, Bruce Moreland wrote: >>>> >>>>> >>>>>On November 21, 1998 at 13:03:07, Robert Hyatt wrote: >>>>> >>>>>>I think their search is difficult to understand. IE I'll point back to the >>>>>>position I posted last year on r.g.c.c about the c5 move in a game against >>>>>>Cray Blitz, in Orlando at the 88 or 89 ACM event. They played c5 after >>>>>>failing high to +2.x, the game went *10* full moves further before *we* >>>>>>failed low to -2.x... I was looking right at their output and they had >>>>>>this incredibly long PV showing that the bishop was going to be lost. They >>>>>>saw it 20 full plies before we did. Lots of micros tried this position last >>>>>>year, and almost all would play c5 (as we expected that reply ourselves in >>>>>>the real game). But *none* had any clue that it was winning material.. even >>>>>>when they went far into the variation... >>>>> >>>>>[Event "ACM 1991"] >>>>>[Site ""] >>>>>[Date ""] >>>>>[Round ""] >>>>>[White "Cray Blitz"] >>>>>[WhiteElo ""] >>>>>[Black "Deep Thought II"] >>>>>[BlackElo ""] >>>>>[Result "0-1"] >>>>> >>>>>1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. f4 e5 >>>>>7. Nxc6 bxc6 8. fxe5 Ng4 9. Be2 Nxe5 10. Be3 Be7 11. O-O Be6 >>>>>12. Qd4 O-O 13. Rad1 f6 14. b3 Qe8 15. Na4 Qg6 16. Bf4 Rf7 17. Qe3 >>>>>Raf8 18. Qxa7 Qxe4 19. Bd3 Qb4 20. Qe3 Ra8 21. c3 Qb7 22. Rf2 >>>>>Qa7 23. Qxa7 Rxa7 24. Be3 Ra5 25. Bb6 Ra8 26. Bc2 Bf8 27. Re1 >>>>>c5 28. Be4 Ra6 29. Rb1 f5 30. Bc2 Rb7 31. Bd8 g6 32. Re1 c4 >>>>>33. Rb1 Bd7 34. Nb2 Ra8 35. Bg5 Rxa2 36. b4 Bb5 37. Re2 Bg7 >>>>>38. Nd1 Ra6 39. Bd2 Nd3 40. Ne3 Ra2 41. Bxd3 cxd3 42. Rf2 Rxd2 >>>>>43. Rxd2 Bxc3 44. Nf1 Bxd2 45. Nxd2 Re7 46. Nf3 h6 47. Rb2 Re4 >>>>>48. Kf2 g5 49. g3 f4 50. gxf4 Rxf4 51. Kg3 h5 52. Nd2 h4+ 53. Kg2 >>>>>Bc6+ 54. Kg1 Rg4+ 55. Kf2 Rg2+ 56. Ke3 Bb5 57. Ra2 Rxh2 58. Ra5 >>>>>Re2+ 59. Kd4 h3 60. Rxb5 Rg2 61. Rb8+ Kg7 62. Rb7+ Kg6 63. Rd7 0-1 >>>>> >>>>>r4bk1/5rpp/1Bppbp2/4n3/N7/1PP5/P1B2RPP/4R1K1 b - - 7 27 >>>>> >>>>>The goal is to search this position and achieve a score of approximately +2. It >>>>>is possible to find the move for other reasons, perhaps a sniff of danger, but >>>>>Bob says that Deep Thought saw to the end of this. >>>> >>>>I do not see something singular in this position >>>>white can play many moves without being -2.xx and even without being-1.xx >>> >>> >>>better look again. First, there is *definitely* something singular if black >>>plays c5. White has to move the bishop. (remember it is black to move in >>>the above game and has to find the move c5 with a score of +2.x for black). >>>If you don't do something right *now* after c5, the bishop is trapped. But >>>it is in fact *very* deep. Deep enough that CB didn't find it... >> >>I do not see how the bishop is trapped after other moves like 28.b4 and I see >>nothing forced in the position(even at move 34 of the game Junior evaluates the >>position as -0.xx with another move Rff1) >>> > >What junior thinks doesn't matter. Cray Blitz thought exactly the same thing >and it searched a good bit deeper than Junior. That was the whole point of this >exercise... this is apparently too deep for any of them, including anything I've >ever done, but it wasn't too deep for deep thought... > > > >>> >>>> >>>>If there are singular extensions then there must be many extensions that begin >>>>far from the root. >>> >>> >>>as I said, perhaps you haven't read Hsu's paper on singular extensions and >>>understand what this algorithm is. But from the initial position, if black >>>plays c5, then white has to walk a tightrope to avoid immediately losing the >>>bishop, and at the end it falls anyway... >> >>I do not see something singular for white. >>Junior5 is going to play 29.h3 after 27...c5 28.Be4 Ra6 with evaluation of -0.24 >>after an hour on pentium200MMX > > >Again, because you don't "see something singular" doesn't mean there is nothing >singular. A "singular move" is nothing more than a move that is about 1/2 of >a pawn (or more) better than all other moves at that point in the tree. I don't >remember the exact singular margin they used, it is in the ICCA Journal, but >that's at my office... But singular extensions happen in lots of places where >you wouldn't think they happen... > > > >> >>Genius3 also play 29.h3 after 1 hour and fifty minutes on pentium100 with >>evaluation of -0.54 > >50 minutes on a P100 has *nothing* to do with the search dt did... and they >don't do the same kind of search by any comparison either... > > > > >> >>I see that white has many options not to lose the bishop so I do not understand >>how singular extensions can help because I do not see one move that is clearly >>better than the others > > >at *any* point in the tree? Not just at the root? Singular extensions >apply 20 plies deep as well as at the root... *every* chess position has >some singular moves when searched... > > > >>> >>> >>> >>> >>>> >>>>If I were white then I would play 28.b4(Junior5 changes its mind from Be4 to b4 >>>>and now to Rd2 without a losing evaluation for white) >>>> >>>>I want to see a tree that prove Junior5 or Fritz5 that the evaluation of the >>>>position is less than -1 (I mean the evaluation at the leaves after search at >>>>tournament time control is less than -1, and the evaluation after every move >>>>of white that go out of the tree is less than -1) >>>> >>>>Uri >>> >>> >>>I'm not sure what you mean "I want to see a tree ..."... I *saw* the output, >>>I was on the *wrong* end of all this... I saw their score, I watched our score, >>>thinking their score was the result of a bug. It wasn't... >>It may be because of a different evaluation function or because of a bug >> >>I do not believe that it is because of a tree before I see a part of the tree >>that convince my Junior5 that black has more than a pawn advantage. >> >>I mean that in every leaf of the tree the evaluation(after search of 3 minutes) >>is more than a pawn advantage for black and white cannot do a move to get out of >>the tree with better evaluation. >> >>Uri > > >I'll try to ship this to you. Do you have a train track close to your house? >because the output might well have about 10 *million* pages of output. :) I did not ask for all the tree but only the tree up to the point that my programs can see by search of 3 minutes that black has at least 1 pawn advantage. This is clearly less positions because if in the leaves it is -2.xx then Junior can see some moves before the leaves that it is -1.xx >I don't have their "output" for this move. As I said before, we sat at the >same table playing this game at the 88 ACM event (I think). I saw their output, >they saw ours. We both saw them fail high with a score > 2.0, while we were >reasonably happy with our score... until the roof fell in about 10 moves >later... and their eval didn't vary by much for the entire sequence... So I >can't give you their output, since I don't have it (they were using a laptop >to display their stuff). I can only tell you what actually happened in the >game. I believe that cray blitz lost because of a mistake that came after c5(maybe at move 32 because I do not see what is wrong with 32.Bg5) The fact that they have score>2.0 does not prove that they were right in the evaluation. I saw newspapers do the same mistake when a human player does a sacrifice and win and they see it as a proof that the sacrifice was a good move. Uri
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