Author: Robert Hyatt
Date: 21:14:53 01/20/03
Go up one level in this thread
On January 20, 2003 at 23:00:55, Ricardo Gibert wrote: >On January 20, 2003 at 21:57:38, Robert Hyatt wrote: > >>On January 20, 2003 at 21:32:22, Ricardo Gibert wrote: >> >>>On January 20, 2003 at 20:44:21, Robert Hyatt wrote: >>> > >[snip] > >>>>Round 6 Crafty vs Searcher >>>> >>>>A near disaster for the first game of the second day. The same d4 opening >>>>led to a similar position, but things did not go very well here. First score >>>>out of book was -.42, which was typical for every 1. d4 game crafty played as >>>>white. But it was able to pull that up quickly normally. 10 moves out of book, >>>>the score hadn't changed, showing that searcher was playing very well and with >>>>a reasonable amount of understanding of the position. >>>> >>>>Finally by move 24, Crafty was back to a slightly + score, and this held until >>>>it started dropping as it misjudged the queen/rook attacking in the center. At >>>>move 32, the score was -.68 after 16 plies. at move 35, the score was -1.5, at >>>>move 40 -2.0, -2.5 at move 50, -3 at move 60, and at this point Crafty dug >>>>in its heels and pulled the score back to -2.3 where it stayed for a long >>>>while. But it slowly traded pawns, and the score started swinting back. By >>>>move 80, it was -2.0 again, -1.5 by move 85, -1.0 by move 95, and it finally >>>>reported a draw score at move 102. Of all the games it played, this was a >>>>really nice effort as it showed a lot of understanding about king rook and pawn >>>>endings, something I have worked on a lot over the years. >>> >>> >>>I find your last sentence surprising. Crafty was very lucky in this game that >>>Searcherx did not play 62...Re8 62.Kxg3 Rb8 winning easily. >>> >>> >> >>Crafty says if you play Re8 it just plays Rb7 immediately, not Kg3. >> >>Score doesn't change much... >> >>It may be overlooking something, but it isn't going to let black get >>the rook behind the pawn... >> >>Maybe we are at the wrong move? IE you have two move 62's above. >>Do you mean 61. Re8? > > >Yes. 61...Re8 62.Kxg3 Rb8 was my intention. > > >> >>Going back to move 61, and playing Re8 Kg3 Rb8 I get Rd4 and Rb4. White >>loses one of the pawns on the h file, but only one. It isn't clear to me, >>without a lot of study, how black makes progress. The pawn is blockaded, so >>the black rook is stuck on the b file unless it gives check. The black >>king can't abandon the kingside or white will eat the g pawn and the hpawn >>should be enough to force the trade of the rook and a draw... > >[D]8/1p1R2pk/5p2/7P/7P/5Kn1/4r3/8 b - - 0 60 > >61...Re8 62.Kxg3 Rb8 63.Rd4 b5 64.Rb4 Kh6 65.Kg4 Rb7 66.Kh3 Kxh5 67.Kg3 g6 >68.Kh3 f5 69.Kg3 Rb6 70.Kh3 Rc6 71.Rb3 Rc4 is a prosaic and convincing win. > >The idea of getting the rook behind a passed pawn for a won rook ending also >occurred in the CCT where both programs (one was Diep) missed it. If I remember >correctly, Diep won anyways by a more circuitous and eventful route. > >In this same tournament, the other idea of abandoning the outside passer to get >2 connected passers also occurred (as in the above augmented analysis). I can't >remember the program names, but that game was particularly funny. The defending >side tried to invite the other side to win in this way (!) and the other program >resisted! I stopped watching the game at this point, so I don't know how it >turned out. > >My point is that Rook endings are a major achilles heal for programs. Part of >the problem is that the programmers really *do* have understand how to play Rook >endings to be able to get their programs to play them well. The trouble is, >learning to play them and then program it is very very difficult. I know of no >program that has done this competently. For example, Ruffian too is blind to the >move 61...Re8. Crafty was expecting this move, but as I said, the score was not a lot different from what actually happened, at least to the depth I searched earlier tonight. It was expecting the same variation you gave, but the effect seemed to be the same here. I won't try to debate whether Re8 is a winning move or not, yet, as it will take some study. But I am not sure how to win after the response Crafty gave, Rd4 and if b5 Rb5. Now the pawn is stopped, and the white king hold the last h-pawn. Not that it isn't winnable, but I didn't see a way with a pretty quick look... > >The proper methods of treating the diagrammed position are stock methods that >are part of every decent endgame players arsenal and so far programs remain >clueless. > If you look at all the endings Crafty played, it at _least_ understands the concept of "rooks belong behind passed pawns." And it is even smart enough to know that doubling behind the pawn is pointless, which many programs will do, thinking that if one behind the pawn is good, two is better. :) > >> >>However, my comments were based on the game itself, as it was played, without >>any long analysis about whether either side made a fatal mistake or not... >> >> >> >>>> >>>>The game ended at move 115 with a repetition. >>>> >>>>Round 7 quark vs Crafty >>>> >>>>18 book moves, score 0 on leaving book, not a bad start as black. A tactical >>>>oversight saw the score drop to +.70 (good for white) at move 21, but this >>>>pawn "sac" was quickly recovered positionally and by move 24 the score was -.10 >>>>and I was breathing easier. By move 30 the score was -.7. By move 65 the >>>>score was nearly equal, and it looked to be headed to another draw. However, >>>>at move 65 quark sacrificed a bishop for crafty's last pawn, leaving it in a >>>>KRB (crafty) vs KNPPP (quark). The bishop/rook quickly ganged up on the >>>>pawns and won them one by one, leading to a krb vs kn endgame table loss for >>>>quark. A good game by quark, and the bishop for pawn looked like a draw, but >>>>with a lot of maneuvering, the two pieces were simply overwhelming. >>>> >>>>Round 8 Pepito vs Crafty (two blacks in a row to offset two whites earlier) >>>> >>>>I didn't know much about pepito, so I simply watched the game. Out of book at >>>>move 7 had a score of -.37 so this seemed promising. Around move 25 the score >>>>started dropping and pepito won a pawn. As in round 6, crafty dug in and by move >>>>63 this was a drawscore game as well. Nothing good or bad to say here, it was >>>>just "a game". >>>> >>>>Round 9 Crafty vs Tao >>>> >>>>A Ruy Lopez that endedthat ended after 11 moves, and after Crafty played >>>>Bh6, Bxh6, Qxh6 and then Qg7 the game instantly turned into a K, two rooks >>>>and two minors for each side ending, with 3 pawns on each wing.. My score >>>>was dead zero here and it really looked like a draw. >>>> >>>>However, around move 24, black moved his rook off the e-file and that >>>>gave crafty a window of opportunity to penetrate, and it did so with a >>>>score of +.5 at move 24. By move 33, the score was solidly at +.5 and >>>>by move 50 it was clear that white was going to infiltrate and eat the >>>>queenside, which it did... >>>> >>>> >>>>All in all an interesting experience. >>>> >>>>Again, as always, the book is critical, and I did _zero_ book preparation >>>>which hurt in several games. Using an automatically produced book can >>>>work, I am convinced, but it needs to include recent games, so that old >>>>lines with refutations are not played. >>>> >>>>The next tournament will find me with a better book. :)
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