Author: Oliver Roese
Date: 02:56:36 05/17/00
Go up one level in this thread
On May 16, 2000 at 09:54:24, Robert Hyatt wrote: >On May 15, 2000 at 23:24:13, blass uri wrote: > >>On May 15, 2000 at 22:43:00, Robert Hyatt wrote: >> >>>On May 14, 2000 at 18:09:20, Pete R. wrote: >>> >>>>On May 14, 2000 at 08:54:35, Jürgen Hartmann wrote: >>>> >>>>>On May 14, 2000 at 08:44:57, Jürgen Hartmann wrote: >>>>> >>>>>>and ...b5 is a possibility for counter play. Frans Morsch will certainly sweat >>>>>>blood and tears at the moment. Small consolation that all other chess programs >>>>>>behave in the same way. >>>>> >>>>>Correction: Crafty 17.10/CB plays 13... exf4!, the only chance to avoid the >>>>>death sentence. >>>> >>>>Well, according to comments from Dr. Hyatt, pawn structure evaluation seems to >>>>be his major tuning focus for Crafty these days. Clearly this is a worthwhile >>>>goal, since computers are already top notch at tactics. But the consequences of >>>>pawn moves are often far too deep for tactical evaluation, so things like this >>>>have to be caught in the positional evaluation. A program *should* be able to >>>>"see", just as a human can, that white has a great pawn structure and will >>>>continue to annex space if f5 is allowed. Not easy to program I suppose. >>> >>> >>>Not easy... not impossible... >>> >>>Very important against these guys... In this case you simply can't allow >>>the e4-f5 pawn chain to happen. The center becomes locked, white has all >>>the space on the kingside, and black is constrained to live in a small shoe- >>>box and wait for jack-the-ripper to show up... >> >>It will be interesting if there is some statistics about the results in the same >>pawn structure after f5. >> >>In how many games the same pawn structure happened and how many games out of it >>white won. >> >>Uri > > >Take a wild guess about how many times this happened to Crafty before I tuned >the eval to not allow a pawn chain like d3/e4/f5. > >:) > >I don't have _all_ the answers to such positions, by any stretch. And crafty >will react violently to such attempts, sometimes so violently that it ends up >with a weak position (but at least it doesn't get crushed after allowing f5). > >It is a very fine line to walk. I still have a lot of work to prevent this >sort of stuff, even though I have worked on king safety repeatedly. It has a >very good idea about open lines around the king, and not allowing them. But it >does, on occasion, defend against a threat that is not serious enough to cause >concern. And in chess, everything is 'give and take'. If you give more than >you take, you can get into just as much trouble as when you allow f5 to be >played... Interesting... Recently i played a lot of games against Fritz 4.01 (100+, i got roughly 20%, each having 15 m/g). A main avenue to success (amongst some others) was to build up such a pawn structure. Computers are very bad in such positions and Fritz is even worse, since he has absolutely no clue there. (But beware! Against most humans it is enough to have a strong attack and they will loose their fate rather soon. Not so against computers. If you sacrifice, every move must be correct otherwise you loose. I lost many games in this manner. ) But against crafty i couldnt manage to get into that... I think this is very important for good performance in a competitive environment. Practically a closed position is more worthy than an extra pawn in an opened position against Fritz under some circumstances. (I mean it.) Oliver Roese
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