Author: Robert Hyatt
Date: 07:51:20 07/26/01
Go up one level in this thread
On July 26, 2001 at 10:11:31, Uri Blass wrote: >On July 26, 2001 at 08:50:40, Ulrich Tuerke wrote: > >>On July 26, 2001 at 08:40:33, Uri Blass wrote: >> >>>On July 26, 2001 at 08:18:42, Robert Hyatt wrote: >>> >>>>On July 26, 2001 at 00:43:48, Bruce Moreland wrote: >>>> >>>>>On July 25, 2001 at 21:26:18, Robert Hyatt wrote: >>>>> >>>>>>On July 25, 2001 at 18:36:08, James T. Walker wrote: >>>>>> >>>>>>>This position arose today in a game between Hiarcs 7.32 vs Century 3.2. >>>>>>>Although Hiarcs searched for 6 minutes on an Athlon 900 with 128M hash and it's >>>>>>>score dropped from the previous 0.87 to -0.56 it still could not resist the BxN >>>>>>>which I believe loses. I think almost any move which saves the Bishop keeps >>>>>>>white alive. Best is probably Kxb4 or Be3. Crafty is very fast to avoid BxN. >>>>>>>Junior7 is slow but finds it in a little over 1 minute. >>>>>>> >>>>>>>[D]8/p4k1p/6p1/8/1p2P1P1/1Kn3P1/3B3P/8 w >>>>>> >>>>>> >>>>>>This is all about knowledge. White's bishop is the only hope to restrain the >>>>>>black passed pawn and also help on the other side of the board. If it goes, >>>>>>black's distant passer makes this a normally won ending for black. >>>>>> >>>>>>I can't imagine a program trading the last piece and giving the opponent a >>>>>>distant passer, just on general principles, unless it sees some sort of tactical >>>>>>trick to sneak in its own pawn even quicker... >>>>>> >>>>>>If a program wants to aspire to be a GM, it _must_ know something about such >>>>>>endings... >>>>> >>>>>The reason a program would take the knight is that being up a pawn in a K+P >>>>>ending is usually better than being up a pawn in a B vs N ending. >>>>> >>>>>I don't think a program "has" to know about this kind of stuff in order to be a >>>>>GM, any more than a human has to be able to find a middlegame mate in 15 in 1/4 >>>>>second, has to be able to demonstrate a winning Fine 70 line in 1/2 second, or >>>>>has to be able to call mate in 95 in a KBN vs KN. >>>>> >>>>>Being a GM is not about being able to blend in perfectly with the GM community. >>>>>It's about being able to generate results comparable to those attained by GM's. >>>>>If the program is stupid in some circumstances, this is not necessarily fatal as >>>>>long as the weakness can be masked. >>>>> >>>>>bruce >>>> >>>> >>>>If a program doesn't know that being a pawn up, but with the opponent having >>>>an outside passed pawn, is most likely lost, then it is not going to be able to >>>>see that with search, >>> >>>Program can see it by search afer enough time. >>>Even Hiarcs that is relatively slow could see it after some minutes on pIII800. >>>Other programs are faster than hiarcs in seeing it but they do not see it at the >>>root like Crafty and they may need 1 minute on PIII800. >>> >>> and it is going to get hit on over and over once the >>>>opponent realizes it. >>> >>>The opponent needs to get into a pawn endgame and in most games the opponent >>>cannot go into a pawn endgame. >>> >>> It happened to me with cptnbluebear many times. Once, >>>>4 games in a row in fact, before Roman said "you _must_ fix this..." >>> >>>When the hardware gets better the program can see more by search and the program >>>may avoid the pawn ending by search. >>> >>>> >>>>I don't think you can mask a weakness that lets a program step into a totally >>>>lost endgame position thinking it is doing a good thing. >>> >>>I believe that Deep search can help here. >>>In the relevant example the program that I tried except Crafty do not know it by >>>chess knowledge but they are not going to fall into the trap at tournament time >>>control. >> >>I think that it is not really satisfying to solve this by search. Then hide this >>position just a bit deeper in the search tree. It can seriously spoil your >>search. >>IMHO it's not difficult to better evaluate this type of position by means of the >>"remote passed pawn" concept. >> >>Uli > >I agree that it is better to solve it by evaluation but I disagree that not >solving it is a big problem in games. > >In most of the games the problem is not going to happen because the opponent is >not going to be able to get the relevant position or the program can avoid the >error by search. > >I will be surprised if there are GM's who can beat Deep Fritz in more than 10% >of the games by trading into a pawn endgames. > >Uri I saw cptnbluebear do it 4 times in a row to Crafty. I watched him do it two games in a row vs Hiarcs (don't remember the version). The programs simply traded down into positions where he had a potential outside passer (candidate) that decided the game in a most trivial way. If you have that kind of hole, and it becomes known, then you just gave the GM a way to exploit your program. And they can and will trade down into endings, and give up a pawn to create a position you don't realize is lost...
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