Author: Robert Hyatt
Date: 08:32:29 08/18/05
Go up one level in this thread
On August 18, 2005 at 11:21:20, Eduard Nemeth wrote: >On August 18, 2005 at 10:51:55, Robert Hyatt wrote: > >>On August 18, 2005 at 10:42:33, Drexel,Michael wrote: >> >>>On August 18, 2005 at 09:48:19, Peter Berger wrote: >>> >>>>On August 18, 2005 at 09:01:51, Majd Al-Ansari wrote: >>>> >>>>>I was watching the game on playchess and looks like Fruit won the game. Very >>>>>impressive game considering Crafty was using 8 processors and Fruit only 1 >>>>>processor. But I have to admit I think that Crafty was caught by poor book >>>>>opening. >>>> >>>>I am not sure I completely agree with this assessment, at least not when put >>>>this way. >>>> >>>>The potentially controversial move is 11. ... g5 I suppose. I don't think this >>>>move is that bad at all, objectively. >>> >>>I hope you know that objectivity doesn´t count in computer chess at all. >>>Crafty 19.19 thinks the position is about +1.2 for White after this move and >>>Fruit 2.1 thinks it is +1. >>> >>>Before that move both think it was equal. >>>So the game was practically decided after this move. >>> >>>Let's move a little further: 12. Qd2 h6 >>>>13. Qc3 Qf6 14. Kh1 . Here Crafty played 14. ...Bb7?, that is clearly a bad >>>>idea. The king has to stay in the centre or castle queenside if necessary, the >>>>bishop belongs to d7 or e6 and then the rooks both belong to the kingside to >>>>attack white's king. >>>> >>>>After 14. ...Bb7 white has an edge, but black is not lost. After 15. f4 gxf4 16. >>>>Bxf4 the next critical point is reached. Here a possible move is 16...Rg8 e.g. - >>>>nothing to brag about, but black is still well alive. Instead 16. ..O-O ?? is >>>>just suicide. >>>> >>>>So yes - this line should never have been in Crafty's book, because it could not >>>>deal with it. I am to blame for that, so maybe 0.6 points were lost because of >>>>that - bad enough !! The rest is Crafty's fault, that just castled into it. >>>> >>>>Congrats to Fruit - nice game! >>>> >>>>Peter >>> >>>Your book did a good job so far. Nobody is able to prevent such things >>>completely. >>>Bob should develop some tool which analyses all the relevant final positions of >>>a Crafty book automatically and in case Crafty does evaluate this positions >>>worse than -0.7 (for example) writes the associated line and score into a >>>textfile. >>>That should make life much easier for his book cooker :) >>> >>>Michael >> >> >>It isn't quite so simple. This wasn't necessarily the "final position". It was >>a "side position" where white could play a move we didn't have in our book. >>Primarily because the move 12. ... g5 is not in any book I have, which took >>Fruit out at a point where the "refutation" was obvious. > >But in a game: > Being played "in a game" is meaningless. I've seen GM players overlook mate in 2 in a game, and I'd hardly want to use their move as a choice... :) >[Event "Salta Clarin op"] >[Site "Salta"] >[Date "1995.??.??"] >[Round "3"] >[White "Ginzburg, Maximiliano"] >[Black "Sorin, Ariel"] >[Result "0-1"] >[ECO "C47"] >[WhiteElo "2440"] >[BlackElo "2500"] >[PlyCount "125"] >[EventDate "1995.??.??"] >[EventType "swiss"] >[EventRounds "9"] >[EventCountry "ARG"] >[Source "ChessBase"] >[SourceDate "1996.11.15"] > >1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. d4 exd4 5. Nxd4 Bc5 6. Nxc6 bxc6 7. Bd3 d6 8. >O-O Ng4 9. h3 Ne5 10. Na4 Bb6 11. Be2 g5 12. Nxb6 axb6 13. f4 gxf4 14. Bxf4 Qf6 >15. Bh5 Be6 16. a4 Rg8 17. Kh1 Qh4 18. Ra3 Nc4 19. Rc3 Ra5 20. e5 Nxe5 21. Re3 >Ke7 22. b3 Ng6 23. Bg4 Nxf4 24. Rxf4 Re5 25. Ree4 Bxg4 26. Qd4 Qh5 27. Rxg4 >Rxg4 28. Rxg4 Re1+ 29. Kh2 Qe5+ 30. Qxe5+ Rxe5 31. b4 Re3 32. Rg8 Rc3 33. Rc8 >Kd7 34. Rh8 Rxc2 35. Rxh7 Ke6 36. h4 Rc4 37. Kh3 Rxb4 38. h5 Kf6 39. g4 Rxa4 >40. Rh8 Kg7 41. Rc8 b5 42. g5 Rf4 43. Kg3 Rf1 44. Rxc7 c5 45. Kg4 b4 46. Rb7 d5 >47. g6 Kh6 48. gxf7 c4 49. Rxb4 c3 50. Rb6+ Kg7 51. Rc6 d4 52. Kg5 Rxf7 53. >Rg6+ Kh7 54. Rh6+ Kg8 55. Rc6 Rf2 56. h6 Rg2+ 57. Kh5 c2 58. Rc8+ Kf7 59. h7 >Rh2+ 60. Kg5 d3 61. Rc7+ Ke6 62. Kg6 Kd5 63. Rd7+ 0-1 > >When not book, then bad playing by Crafty. > >My Comment read here: > > >http://f27.parsimony.net/forum67838/messages/910.htm > >Regards, >Eduard, > >> >>This just happens. In Cray Blitz I had a utility that would "walk through" the >>book, and search at _every_ position. And it caused just as many problems by >>suggesting that a "pawn grab" was safe when it was not, or vice versa, so it >>ends up either being a "learning" thing, or a human analysis problem. >> >>This is what makes this kind of book preparation so very difficult to pull off. >>Not only do you have to look at the position at the _end_ of the book line, but >>you also have to study the positions all along the line from the root to the >>end, to make sure that there is not some tactical shot that was overlooked. >>I've seen that happen _many_ times. Follow common GM opening moves and suddenly >>_wham_. A move nobody had noticed. In the Cray Blitz days, Bert Gower used to >>spend weeks playing through book lines. When he was preparing white openings, >>he would step through every position, making CB do a deep search for black >>(without book) at every move in the path, to see if there was some deep tactical >>thing that had gone unnoticed previously... It was immensely time-consuming. >>Probably what i should do today is to run on our 128 node cluster, and play >>crafty with book vs crafty without book, to let that pick up the bad openings >>and cull them with learning. That at least would get through a lot of games in >>a hurry, playing 128 at a time...
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.