Author: Rafael Andrist
Date: 08:32:25 01/11/03
Go up one level in this thread
On January 11, 2003 at 10:04:28, Jeroen Noomen wrote: >What is 'blocked' in your opinion? blocked (completely): after removing all pieces, the number legal moves of the remaing paws is zero. other possibility (includes more positions, but needs more time to recognise): after removing all pieces, the game (pawn moves only) cannot lead to material changement, i.e. the pawns are either blocked or if they advance, they get blocked without possibility to capture or beeing captured. This is still fast if you use pawn hash. >How do you recognise that the rooks cannot >get in? How to define that? Do you know MS Paint where you can colour areas with a mouse click? It works similar here, but with bitboards and the pawns do limit the area. So you can see staticaly that White needs to sacrifice one rook. And White cannot make any captures -> it is a draw This is a pattern you can code without problems and you can recognise many of these blocked positions. If White could make captures, it can only make progress by capturing which you can use to prune the search - and then hopefully see that the captures lead to draw/loss. >And most important: Why bother with this position, >which will never occur in a game? Because it is possible to catch a whole class of blocked positions. >>Of course you can never catch all exceptions, but to detect the most important >>ones only is not that time consuming. >What are 'the most important ones'? That depends on the programmer and what he wants to implement. I consider as important the typical fortresses with bishops/pawns, knights/pawns ,sometimes with rooks which can be found in the endgame books and anything with pawns only. >Do you think this position above is an >important exception? I don't think so. Besides, modern programs are programmed >not to block the position in this way. So it is pretty useless IMO to solve it. That's their problem if they prefer to loose rather than saving the draw by blocking the position. regards Rafael B. Andrist
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.