| As in the orthodox game, win by checkmating the king. It shouldn't be able to
| escape the check, not even by moving to the other board.
-p Note: en-passant and castle occur as they do in the standard game.
+p.
+ Note: en-passant and castle occur as they do in the standard game.
+ More specifically, en-passant is possible regardless of the worlds pawns are in.
+ This is justified because pawns "go through the mirror" while moving, and can
+ thus be captured either right after or just before they pass the mirror.
+ Castling should be legal according to orthodox rules on the board 1 (it cannot
+ occur on board 2, because it would mean king and rook moved). Moreover, the
+ king cannot be in check on board 2 after castling.
h3 Credits