Author: Vincent Diepeveen
Date: 08:59:20 01/24/01
Go up one level in this thread
On January 24, 2001 at 00:14:36, Robert Hyatt wrote: >On January 23, 2001 at 17:59:25, Vincent Diepeveen wrote: > >>On January 22, 2001 at 17:13:17, Uri Blass wrote: >> >>>On January 22, 2001 at 16:02:56, Robert Hyatt wrote: >>> >>>>On January 22, 2001 at 14:55:49, Peter Berger wrote: >>>> >>>>>A tough position it seems . >>>>> >>>>>Although none of them is "mine" , a try : >>>>> >>>>>"Bringer" >>>>> >>>>>0:00:00.1 ( 4/12) 3891 4.87 f6-e6 d7-f7 f5-f6 >>>>>0:00:00.2 ( 5/13) 17765 4.83 f6-e6 d7-f7 h2-h4 a5-a4 e6xf7 g8xf7 >>>>>e5-e6 f7-e7 h4-h5 >>>>>0:00:00.5 ( 6/15) 58783 4.72 f6-e6 d7-f7 h2-h4 a5-a4 e6xf7 g8xf7 >>>>>e5-e6 f7-e7 >>>>>0:00:00.7 ( 6/16) 86563 4.73 f6-g6 >>>>>0:00:01.9 ( 7/18) 212939 4.72 f6-g6 g8-f8 g6-h6 f8-g8 h6-e6 >>>>>0:00:05.1 ( 8/23) 645145 4.74 f6-g6 g8-f8 g6-h6 f8-g8 h6-e6 >>>>>0:00:13.4 ( 9/27) 1869222 4.61 f6-g6 g8-f8 g6-h6 f8-g8 h6-e6 >>>>>0:00:17.1 ( 9/27) 2428949 4.63 f6-e6 d7xe6 f5xe6 g8-f8 >>>>>0:00:29.8 (10/30) 4346163 4.23 f6-e6 d7xe6 >>>>>0:00:30.8 (10/30) 4559520 3.83 f6-e6 d7xe6 >>>>>0:00:32.7 (10/30) 4871934 1.97 f6-e6 d7xe6 f5xe6 g8-f8 d5-d6 c7xd6 >>>>>e5xd6 a5-a4 h1-g1 b4-b3 a2xb3 a4-a3 d6-d7 >>>>>0:00:41.8 (10/30) 6179798 1.98 f6-g6 >>>>>0:00:42.7 (10/30) 6346445 2.48 f6-g6 >>>>>0:01:34.8 (10/36) 13206630 2.49 e5-e6 >>>>>0:01:44.8 (10/36) 14944128 2.99 e5-e6 >>>>>0:02:03.3 (10/36) 17506577 3.00 f6-g5 >>>>>0:02:28.9 (10/36) 21440299 3.35 f6-g5 g8-f8 d5-d6 >>>>>0:03:57.7 (11/36) 34278234 3.26 f6-g5 g8-f8 d5-d6 >>>>> >>>>>So , Bringer might be lucky and avoid it at fast blitz time control but needs 43 >>>>>secs to avoid it for the right reasons it seems . >>>>> >>>>>In fact this position is a hard challenge for the commercials, too : >>>>> >>>>>"Century 3" >>>>> >>>>>00:00:24 11.00 10.63 1.De6+ Dxe6 2.fxe6 Kf8 3.d6 cxd6 >>>>> 4.exd6 a4 5.d5 a3 6.d7 Ke7 7.h4 >>>>> b3 8.d6 Kd8 (23) (0.00) >>>>> >>>>>00:00:50 12.00 8.02 1.De6+ Dxe6 2.fxe6 Kf8 3.d6 cxd6 >>>>> 4.exd6 a4 5.d5 a3 6.d7 Ke7 7.h3 >>>>> b3 8.d6 Kxe6 9.d8 (32) (0.00) >>>>> >>>>>00:03:00 13.00 0.44 1.De6+ Dxe6 2.fxe6 Kf8 3.Kg2 a4 >>>>> 4.d6 (159) (0.00) >>>>> >>>>>No news after 15 minutes , so probably Rebel can't avoid it at tournament time >>>>>control . >>>>> >>>>>Both tried on PIII500 . >>>>> >>>>>pete >>>> >>>> >>>>The problem is endgame knowledge. A program _ought_ to know that if you have >>>>a passer, then trade pieces to reach a won ending. Only in this case, that >>>>heuristic back-fires as it is black who ends up winning. This is a _tough_ >>>>exception to handle... >>>> >>>>although a GM would tell you instantly "No I won't trade queens..." >>> >>>IM's and FM's would also say it instantly. >> >>Sorry i hope to get IM real soon (year or 2), >>but i was amazed it lost for white. With king on g2 >>white has a very simple win here. >> >>The whole problem here is a tactical problem as you win a tempo >>with black because of the promotion check by black. >> >>So in short this problem is not very valid, it's just a lucky >>shot that black wins. At first sight i might have traded too. >>If i would play a 40 in 2 game for sure i would not trade as >>i would see for sure that qe6 doesn't walk as fast because of >>the check. >> >>When i saw the post that black wins in this position after qe6 >>i directly realized the check was the problem and *not* the >>rest of the board. So in short it's just a lucky shot of black >>which proves why playing on safe like i do as a human is always winning >>quite chanceless in positions like this. >> >>If i would have had white then my king WOULD have been on g2, >>i can assure you that :) >> > > > > >There is more to it than just handling checks. a program needs to realize >that the b-pawn is a passer. And even more importantly, it is a passer that >is too far from the king to be stopped if there are no pieces left. Oh well, Diep knows this of course and any program will after 6 ply or so realize that it gets a passer, but still it of course prefers Qe6 initially here. Idem for me, but because i'm a human who's always scared making a mistake i would go calculate. So as a human i solve it because of search. In 99 out of 100 similar positions white will still win. Nothing as slow as a majority that runs. A passer mass like this is going to win from it nearly always. Basically what you should see here is the tactical line with the check fast. Cool stuff for my new passer extensions... Note a human is quite effectively calculating this. I just count like next: passer needs x steps to promote with a check. white needs y steps to promote. Then i already have a notion that this race is going to be very close and in this case that black will promote first, without realizing of course whether you need to go for the perpetual check then, or whether black can win it. On the other hand if the white king is on g2 it's a clear win for white after you see next line: qe6 qxe6 dxe a4 e7 kf7 e8Q kxe8 h4 etc. So most likely this position is a bit TOO complex to stand still at just eval here. Of course i'm very happy everyone is starting to realize slowly how important evaluation is, but this is of course an ever going on problem. If any program wants to progress it needs to learn more about chess. Compared to a human a program has nowadays very little weak chains, but all weak chains are chess knowledge dependant very clearly. Both openingspreparement with some of us and evaluation for all of us. >The thing that looks hard is that white has all those passers, and any decent >program should know that passers get stronger as pieces come off the board. >But they also have to know about candidate passers. As that is the deciding >thing in this position. As a human I took about 5 seconds to realize that >trading queens was NFG. Because of the black a/b pawns. Depends. Some humans never exchange, i as a chessplayer always exchange. I would go for Qe6 in blitz probably. >There will come a time when my program, (at least) knows this just as well, >but spots it in microseconds... Otherwise, this is just another hole to >exploit. This combination is simple a certain depth. You need to see the promotion with check, that's all there is. If you add passer extensions you already find this at like 9 or 10 ply or something. No big deal this position. It shows however that the human 'safe' way of playing is much preferred and that using primitif evals like most progs have are asking for trouble. This trick only is in this position because white didn't play on safe some moves ago! So in the end it sure is an eval problem! >>>>And no, there is no point in starting another "is the computer a GM?" >>>>thread. So long as they can fall for these positions, the answer is pretty >>>>obvious. >>> >>>No. >>> >>>By the same logic you could claim that they are also not IM's and not FM's. >>> >>>The only test is games and Rebel proved that it can win a match of 6 games >>>against a GM so it seems to be better than part of the GM's inspite of some >>>weaknesses. >>> >>>Uri
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