Author: Andrew Dados
Date: 10:38:49 01/29/02
Go up one level in this thread
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
Black Knight attacks white King, so it is a check.
To restate those rules: Whichever side can capture opposite King _first_, wins.
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