En Passant Explained: The Rule Nobody Believes Is Real

En passant is a special pawn capture: when an enemy pawn advances two squares from its starting rank and lands directly beside your pawn, you may capture it as if it had only moved one square. You must do it on the very next move or the right disappears forever. It is a real rule, it has been standard for centuries, and no, your opponent did not just make it up to steal your pawn.

The exact conditions

All three must be true. Not two. Three.

1. The enemy pawn moves two squares from its starting rank in a single move. A pawn that arrived next to yours in two separate one-square steps does not qualify.
2. It lands directly beside your pawn, on the same rank, on an adjacent file. Your pawn has to be on its fifth rank for this to even be possible.
3. You capture immediately, on the very next move. Wait one turn and the window slams shut. En passant does not roll over. There is no en passant savings account.

The capture itself: your pawn moves diagonally forward into the square the enemy pawn skipped over, and the enemy pawn comes off the board. Your pawn ends up behind where the captured pawn was standing. This is the part that breaks people’s brains, because it is the only capture in chess where you do not land on the square the captured piece occupied.

Why the rule exists

Blame the pawns themselves. For most of chess history, pawns could only move one square at a time. When the two-square first move was introduced (roughly the 15th century, to speed up openings), it created a loophole: a pawn could sprint two squares and slip past an enemy pawn that would have captured it after a one-square move. En passant closed the loophole. The two-square move saves you time. It does not grant diplomatic immunity.

The name is French for “in passing,” which is exactly what the doomed pawn was attempting.

How to write it down

Standard notation: the file your pawn started on, then the square it lands on, sometimes with “e.p.” for clarity. If your d5 pawn captures a pawn that just played e7 to e5, you write dxe6. Note the destination: e6, the square the enemy pawn skipped, not e5, the square it was standing on. If your scoresheet says dxe5, you have written down a move that did not happen.

The confusions that will not die

• “You made that up.” No. It is in the FIDE Laws of Chess. Every legitimate chess app supports it. If your app “does not allow it,” the conditions were not met, or the app is a coaster.
• “I can do it whenever I want.” Only on the move immediately after the two-square advance. This is the one people learn the hard way, usually mid-plan.
• Only pawns capture en passant, and only pawns get captured. A knight sitting beside a sprinting pawn gets no special privileges. Neither does anything else.
• “It must be optional, right?” It is optional in the way any capture is optional, with one famous exception: if en passant is your only legal move, you have to play it. The rules do not care about your feelings.
• The two-square move itself is fine. Beginners sometimes conclude the sprint is risky and stop playing it. Wrong lesson. The two-square move is usually great. Just know that a pawn on the adjacent file, on its fifth rank, has one turn to do something about it.

The real reason to learn it

Not just so you can play it. So you can stop losing pawns to it, stop accusing honest opponents of cheating, and stop being the person in the comments asking why the computer “glitched.” En passant is not a glitch. It is a 500-year-old trap door, and now you know where it is.