Author: José Carlos
Date: 06:27:53 12/03/04
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On December 03, 2004 at 07:26:24, Vasik Rajlich wrote: >On December 02, 2004 at 14:51:04, José Carlos wrote: > >> >>>What is the definition of closed files? >>>By movei's definition closed files are files that are not open and >>>open files are files when there is no friendly pawn that prevent the rook to >>>go forward(there may be pieces or pawns of the opponent that prevent it to go >>>forward but if you remove all pieces except friendly pawns the rook can go to >>>the 8th rank). >>> >>>By movei's definition the b file is an open file because there are no friendly >>>pawns in that file. >>> >>>Movei has a bonus of 0.1 pawns for rook on open file and panelty of 0.1 for >>>closed file and I am not sure if that bonus and panelty is productive. >>> >>>It was productive in the positions that I tested at the time that I implemented >>>it but I did not play enough games and it is possible that the positions were >>>misleading and in different positions I could get different results. >>> >>>Uri >> >> If there is an enemy pawn in an open line, and it's defended by another pawn, >>that's not likely to be a useful place for a rook. >> The definition to open line is a line without any pawn. >> A closed line is a line with a friendly pawn. >> A semi-open line is a line with no friendly pawn but opponent's pawn. >> Those three should have IMO different bonus/malus. >> It is also important to check if a rook in a line can eventually move into >>enemy's position. For example, in the following position: >>[D]r2qkbnr/p1pppppp/1b6/8/8/8/P1PPPPPP/1RBQKBNR w Kkq - 0 1 >> The rook is not very useful in b1. Same for this position: >>[D]r2qkbnr/p1bppppp/2b5/2p5/8/8/P1PPPPPP/1RBQKBNR w Kkq - 0 1 >> >> José C. > >Just one thing to add here: these positions are pretty much the worst-case >scenarios for a totally open file, and they're nowhere near as bad as some of >the bad half-open-file cases (as for example from Movei-Junior). If you're going >to give automatic bonuses, it seems that the bonus for a completely open file >should be quite a bit higher than for a half-open file. > >Vas The good thing for checking this kind of "false" open lines and give them a small penalty compared to "true" open lines, is that the program has something to do, some "plan". For example, in the first position above the program will tend to disturb the bishop with the a or c pawn. In the second, the program will try to exchange one of the bishops to get a square to move the rook to. The penalty must be very small, of course. These plans make sense if there's nothing important to do first. José C.
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