Single Comment

I agree with Ralph on castling--if his colorbound rule isn't sufficient,
the game designer should spell it out.  Here is a proposed general castling
rule for 'build your own army' type variants in which the designer can't
know what piece will be in the corner:

The King can Castle with whatever piece is in the corner, even though that
piece is not a Rook, and of course the usual restrictions and rules on
Castling apply. 

Definition: a 'possible square' for a piece is a square it could reach by a
series of one or more moves on an empty board, disregarding special moves
such as castling, pawn promotion, etc.


Castling kingside uses the first rule which results in the corner piece
moving to a possible square.
1. King to g-file, corner piece to f-file. (Normal castling)
2. King to h-file, corner piece to g-file.
3. King to g-file, corner piece to e-file.
4. King to g-file, corner piece to d-file.
5. king to g-file, corner piece to c-file.
6. King to g-file, corner piece to b-file.
7. King to g-file, corner piece to a-file.
If none of these rules apply, castling kingside is not allowed.


Castling queenside uses the first rule which results in the corner piece
moving to a possible square.
1. King to c-file, corner piece to d-file. (Normal castling)
2. King to b-file, corner piece to c-file.
3. King to a-file, corner piece to b-file.
4. King to c-file, corner piece to e-file.
5. king to c-file, corner piece to f-file.
6. King to c-file, corner piece to g-file.
7. King to c-file, corner piece to h-file.
If none of these rules apply, castling queenside is not allowed.

(The concept: if normal castling is not allowed, we try shortening the
corner piece's move and put the King next to it; if this also doesn't work,
we try lengthening the corner piece's move and put the King on its normal
castling square.)