Author: Robert Hyatt
Date: 17:08:41 08/04/99
Go up one level in this thread
On August 04, 1999 at 17:32:51, Ricardo Gibert wrote: >On August 04, 1999 at 16:30:38, Robert Hyatt wrote: > >>On August 04, 1999 at 14:40:31, KarinsDad wrote: >> >>>On August 04, 1999 at 14:09:18, Bruce Moreland wrote: >>> >>>> >>>>On August 04, 1999 at 12:16:52, Dann Corbit wrote: >>>> >>>>>As a 'for instance': >>>>> >>>>>Suppose that on promotion, a program sees that it can promote to a knight >>>>>instead of a queen, and get a king fork, taking a bishop, followed by a queen >>>>>fork, taking the other bishop. In such a case, it might evaluate: >>>>> -pawn+knight+bishop+bishop+two_bishop_bonus+(minor positional goo) >>>>>verses >>>>> -pawn+queen >>>>>and get something a fraction more valuable than a queen. But down the road I >>>>>would rather have the queen than a knight and remove the two bishops. >>>>> >>>>>How do programs deal with this? >>>> >>>>You are really saying you'd rather have a queen against two bishops than be a >>>>knight up, right? >>>> >>>>bruce >>> >>>Actually, assuming an equal game, it is a preference of being up a queen for a >>>pawn as opposed to being up a knight and two bishops for a pawn. >>> >>>Of course, decisions like these are always based off of the actual position, but >>>here is a comment Kasparov made just the other day on Ponomariov - Al Modiakhi >>>in round 1 of the championship: >>> >>>"Looking at Ponomariov's 7.Be3 with 8.Bb6 I have sensed chess of the very >>>distant future. With my limited knowledge of the game I would consider 3 minor >>>pieces in such position much better than Queen+pawn". >>> >>>So, there are obviously positions where having 3 minors is better than having >>>the queen. >>> >>>KarinsDad :) >> >> >>I think that in almost _all_ cases, three minors pieces are better than a >>single queen.. and most games I have seen where this happens are wins for the >>three minors. I don't like two minors and 3 pawns vs a queen however, unless >>maybe if the pawns are all on the 6th rank or farther along. :) > >I felt pretty sure about this too, but I analyzed with Jack Peters a particular >position and came away with idea that it was a lot closer than I thought and >that subjective factors have a big impact. I still prefer the 3 pieces, but now >I am more careful. The 3 pieces don't organize themselves very quickly, but the >Q is relatively much faster in this respect. It depends very much on the >position. > >Related to this topic is R+P+P vs B+N. You have indicated that you set this as >equal. At first I thought this was a mistake, but then I thought about it and >this may be right for chess playing programs, since they are not sufficiently >effective in getting the rook into play. As a human, I use R+P < B+N < R+P+P. I >believe this is the "normal" evaluation. R+P+P = B+N is a practical choice for >computers. Of course subjective factors must be considered. I have done that for a long time... but IM Larry Kaufman published an article in Chess Life (not about computers particularly) about such material imbalancess, and he concluded after looking at a lot of games, that two pieces are about equal to R+P+P. Of course, if the two pawns are on the 7th, that goes out the door, naturally... or if they are connected passers that can roll quicker than the two pieces + the king can mobilize to win them...
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