Author: Will Singleton
Date: 10:36:14 01/29/02
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On January 29, 2002 at 13:15:46, Russell Reagan wrote: >From the FIDE Laws of Chess: > >"Article 9: Check > >9.1 >The king is in "check" when the square it occupies is attacked by one or more of >the opponent's pieces; in this case, the latter is/are said to be "checking" the >king. A player may not make a move which leaves his king on a square attacked by >any of his opponent's pieces. > >9.2 >Check must be parried by the move immediately following. If any check cannot be >parried, the king is said to be "checkmated" ("mated"). > >9.3 >Declaring a check is not obligatory. >[Merely polite! Playing an illegal move does not imply the loss of the game: see >Article 8.1.]" > >Article 9.1 states, "The king is in "check" when the square it occupies is >attacked by one or more of the opponent's pieces." This is the part I'm >particularly interested in. Let's take the following position. > >[D] 8/4k3/3n4/8/1B2K3/7P/8/8 w - - 0 1 > >What is defined as attacking a square? In this position, the knight is sort of >attacking the king, but it can't move to any square. So if it were black's turn >to move, the knight couldn't capture the white king, so is it really attacking >the white king? I believe this does happen to be check, from my experience in >playing chess and reading about it, but I'm trying to find the justification for >it being check. From a scientific/evidence based view, the only justification I >can come up with is that this is not check. > >I can find no definition of attack in the dictionary that would put the white >king in check in this position. The closest definitions that I could find were, >"To fall upon with force; to assail, as with force and arms; to assault" and "to >threaten (a piece in chess) with immediate capture" (most other definitions had >some form of human factor such as incorporating emotions). In this position, the >knight is not in any way falling upon the white king with force, assailing with >force or arms, or assaulting. The second definition which is specific to chess >also does not put the white king in check. The black knight is not threatening >immediate capture of the white king since on black's move, the knight cannot >move, and therefore cannot capture any piece, including the white king. If I >were to attack you, I would undertake offensive actions against you, probably >with the intent of harming you in some way. The black knight, in fact, can bring >no amount of harm to the white king because he himself is unable to move, >leading one to believe that the white knight is not attacking the white king, >thus the white king is not in check in this position, even though common sense >and experience tells us that the white king is in check. > >If someone could point out the source of the rule that makes the white king in >check in this position and clarify what is check and what isn't, along with what >is defined as attacking a square and what isn't, I would appreciate it. > >I got to thinking about all of this in the debate over whether to generate 100% >legal moves and detect pins statically or whether to let the illegal moving of >pinned pieces be handled by retracting moves that lead to positions where the >side not to move is in check. The definition of what is an attack and what is >not matters greatly here. If a pinned piece can attack, then either method of >generating legal moves is fine. If a pinned piece cannot attack, then you can't >use the method of retracting moves of pinned pieces, since you would end up >having to detect if the piece attacking the king is pinned, when you end up >doing static pin detection anyway. > >Perhaps the rules need to be clarified, because there seems to be somewhat of a >contradiction. I look forward to hearing people's thoughts on this. > >Russell I don't share your enthusiasm for this issue. A check is a check, by rule. Whether a piece can actually carry through on an attack is irrelevant. imho. Will
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