achillesheel
♡ 61 ( +1 | -1 ) loverCheck out the FIDE rules under "More Options":
A pawn attacking a square crossed by an opponent's pawn which has advanced two squares in one move from its original square may capture this opponent's pawn as though the latter had been moved only one square. This capture can be made only on the move following this advance and is called an 'en passant' capture.
Here is a link to a web page illustrating en passant (and other rules): www.chessvariants.com/d.chess/chess.html>