En Passant is a special pawn capture rule. It literally means "in passing" in French. It occurs when a pawn moves two squares forward from its starting position and lands directly next to an opponent's pawn.
The "Invisible" Capture: You can capture the enemy pawn as if it had only moved one square forward. Your pawn moves diagonally to the empty square behind the enemy pawn, and the enemy pawn is removed from the board.
En passant is a unique exception to the standard rules of capture because it is the only time in chess where a piece is captured on a square it is not actually standing on. This rule was introduced alongside the "double-step" initial pawn move to prevent pawns from using their new speed to bypass enemy pawns without the risk of being captured. Because it is a fleeting opportunity, the capture must be made on the very next move; if the player chooses to do something else, the right to capture that specific pawn en passant is lost forever.
Important Conditions:
- The capturing pawn must be on its 5th rank.
- The enemy pawn must have moved two squares in a single move.
- The capture must be made immediately on the next turn.