Author: Amir Ban
Date: 00:03:26 11/22/98
Go up one level in this thread
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) >> >> >>> >>>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 > >Genius3 also play 29.h3 after 1 hour and fifty minutes on pentium100 with >evaluation of -0.54 > >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 >> >> >> >> >>> >>>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 Are there examples of singular extension moves by Deep Thought/Deep Blue that are more obvious than this one ? Amir
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