From: Martin DeMello <martindemello@...>
Date: 2005-06-21T13:25:36+09:00
Subject: Re: [SOLUTION] Chess Variants (II) (#36)

Glenn Parker <glenn.parker@comcast.net> wrote:
> James Edward Gray II wrote:
> > On Jun 20, 2005, at 6:14 PM, Glenn Parker wrote:
> > 
> >> It's not that simple.  It may be possible to capture the attacking  
> >> piece without moving the king.  If two pieces are attacking,  
> >> capturing one of the pieces may block the other piece's attack.
> > 
> > Double check rules out everything but moving the King, so that should  
> > be an easy enough special case to handle, if you can spot it to begin  
> > with.
> 
> Um, no.  Double check does not rule out everything but moving the king. 
>   Read the last sentence of my original reply again.

If capturing a piece blocks the other piece's attack, then the original
piece must necessarily have been blocking the other piece's attack too
(at least with the standard piece set and rules). The one loophole might
have been a pawn jumping two squares, imposing both direct and
discovered check, and being captured en passant in such a way that the
discovered check is blocked (that's the only instance where a capturing
piece doesn't occupy the square of the piece it captured), but looking
at the way the pieces move that's impossible too.

martin