Author: Norm Pollock
Date: 07:34:56 03/18/05
Go up one level in this thread
On March 18, 2005 at 09:07:50, Dimitris Poulos wrote: >I wouldn't think so anymore. Since almost any game contains blunders and Norm's >discussion on percentages of won games some weeks ago, I would consider as fair >a book that keeps this percentages. Or a book with all GM games except the >innovations better. >Just to ponder. > >Dimitris All games contain blunders. No person or computer knows how to play the perfect game. Even drawn games are not perfect. Assuming these three premises, how do you make up the best possible opening book? First get a large collection (100,000+) of long time control games between (human) professional players (elo 2400+ perhaps). Second, use recent games, especially games from the "computer age" (say year 2000+). Professional players today practice their openings on computer and look for innovations from the computer. So by using recent games, you are getting the advantage of computer analysis to some extent. Third, eliminate shorter games (20 moves or less perhaps) that probably have an opening blunder or were grandmaster draws. Fourth, check the collection of games to be sure that all games have results, and that all games have elo ratings within the range you want. An often used approach is to filter out "bad" moves by indicating each individual "bad" move with some sort of NAG. But to do this right, you would need to be sure which moves are "bad". And you would have to go through 100,000 games, move by move. When the engine sees the nag, it will avoid that move. The approach I recommend is to use separate books for white and black. Then use "quantity" of repitition to effectively discard questionable moves. If you have a book of say 60,000 games involving professional players, then choosing only those moves that have occurred 12 times (0.02%) or more seems reasonable. Unfortunately most engines and interfaces do not use separate books so it is even more important in these cases to use a high repitition rate (at least 0.02%). How do you make separate books? For white, take only games white has won. There still could be blunders in the openings that black did not see, but that will be minimal since white won the game against a professional opponent. For black, there will not be as many games that black won compared to white. So use games that black either won or drew. Similarly there will be blunders that white did not see, but they will be minimal because black did not lose. If you can put effective nags into the book(s) as well, then it is even better. Btw, if you go this route, you might want to look at a collection of games (normbk02.pgn) and a pgn utility (elopgn.exe) that I have uploaded at: http://www.crafty-chess.com/down/Pollock/
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.