I have a follow up question. You cannot castle if you are in check or if your king would have to move through an attacked square. But can you castle if your rook would have to move through an attacked square? What if your rook is currently under attack, can you castle then? These are rare occasions, but have almost happened in a couple of my games.
The logic of the principle is that the king should not be in check in any of the places it passes while castling. The rook is of minor importance in that context, i.e. if you have white rook an A1 and king on E1 (and no pawns), you can castle with black queen on A6 & B6, but not C6, D6 or E6.
thanks. I just wan't sure if moving your rook through an attack (esp. from a lesser piece like a bishop that you'd be happy to lose in exchange for it) would be similar to the situation that caused en passent to arise. But then again, because the rook could always jump past the attack if moving on it's own then I suppose not.
Thanks Again.
Jon