Author: Robert Hyatt
Date: 11:47:28 05/07/01
Go up one level in this thread
On May 07, 2001 at 13:14:08, Vincent Diepeveen wrote: >On May 06, 2001 at 21:43:37, Robert Hyatt wrote: > >>On May 06, 2001 at 08:35:07, Vincent Diepeveen wrote: >> >>>On May 05, 2001 at 12:01:08, Dana Turnmire wrote: >>> >>>> Here is an interesting article found in a 1989 CCR article. >>> >>>Exactly the biggest misunderstanding in chessbooks is that 2 rooks >>>are stronger as a queen. Even in most endgames a queen wins easily >>>against 2 rooks. >> >>I wouldn't say in "most". I would say in "some". Two rooks can box up >>a queen and make it impossible to win since the queen can't overpower the >>two rooks without the help of the king... > >Please print the first 1000 positions crafty sees 2 rooks against >a queen. You'll see a tactical mess. That's logical that it is a >tactical mess as otherwise you would NULLMOVE. > >Then figure out who wins. A queen is superior in picking up hung >material. > I found two games real quick, between diep and Crafty. Crafty won both with two rooks. You were watching one in fact a couple of months back. Your bonus for the queen was ridiculous. The queen might be better if the opponent's pawns are wrecked. But if not, the two rooks can pick off pawns and the queen can't stop them. > >> >> >>> >>>However grandmasters only get the exceptions on the board, so if a >>>GM gets 2 rooks versus a queen then *usually* the 2 rooks are stronger. >>> >>>My piece values are about this: >>> pawn 1000 >>> knight 3625 >>> bishop 3675 >>> rook 5800 >>> queen 11750 >>> >>>However there are always things wrong in piece values. >>> >>>In the above values an obvious problem is that a queen is stronger >>>as 3 pieces which is NOT true. >>> >>>Also 2 pieces in the above example are very close to rook+pawn. >>> >>>However i have special code for that to fix it :) > >>Why not just use normal piece values and fix the rest of the problems by >>evaluation, rather than faking up oddball piece values? Crafty uses 1,3,5 and >>9, and has _no_ problems recognizing that two pieces for a rook and pawn is >>a bad trade, as is a queen for three minor pieces... > >I have mobility+activity+centercontrol+scanning of all of my pieces >in DIEP. > >Rooks get huge mobility scores. A rook at 7th rank might >easily get 2 pawns bonus for just activity depending upon the >position. > >If 2 rooks get that at the 7th rank then 11.75 for a queen isn't >so much suddenly... Then you ought to re-think those bonuses as they are getting you killed against computers. Against Crafty you gave up two pawns to get a queen vs two rook ending. You were down _three_ pawns total and were happy. Not a good plan, IMHO... During that game you even said yourself "my queen for two rook bonus is way too big here..."
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