The en passant rule
The strangest rule in chess, and the one every new player is convinced their opponent just made up. It is real, it is five hundred years old, and it exists to stop pawns sneaking past each other.
- Pawns only
- One move window
- Since the 1400s
En passant is French for "in passing". If a pawn uses its two-square first move to land directly beside one of your pawns, you may capture it on the very next move as though it had only gone one square. Your pawn moves diagonally to the square it skipped, and the enemy pawn comes off the board even though your pawn never lands on it.
Before: Black decides how far to push
Black to move, with a pawn on d7 and White's pawn waiting on e5. The pawn on d7 has a choice: one square to d6, where the white pawn can take it normally, or two squares to d5, past it.
The capture, move by move
The whole thing in two moves
Black plays the double step and lands beside White's pawn. White answers with exdd6 written properly as exd6, the pawn moving diagonally to the empty square d6, and the black pawn on d5 is removed. The engine produced both moves and both positions.
1...d5 2.exd6
The black pawn is gone and the white pawn stands on d6. This is the only capture in chess where the captured piece was not on the square the capturing piece moved to.
The window is exactly one move wide
You must take immediately. Play any other move and the right is gone for the rest of the game, and it does not come back. Put the same position to the engine after one quiet king move each and the capture is no longer a legal move at all.
That is the part that catches people. En passant is not a standing option against a pawn that once jumped past you. It is a single reply, on the single move that follows.
Every condition, in order
- The capturing piece is a pawn. No other piece can capture en passant, ever.
- The captured piece is a pawn that has just moved two squares from its starting rank.
- It landed directly beside yours, on the same rank, on an adjacent file.
- You capture on the very next move. One move of delay and it is gone.
- Your pawn is on the fifth rank if you are White, or the fourth if you are Black. That falls out of the rules above rather than being separate.
Why the rule exists at all
Pawns originally moved one square at a time. The two-square first move was added in the fifteenth century to speed up the opening, and it created a hole: a pawn could now run past an enemy pawn that would have been able to stop it under the old rules. En passant patches exactly that hole and nothing else, which is why it only ever applies to the double step.
It is also compulsory in one narrow sense that surprises people: it is not compulsory at all. Some very old rule sets required it. The modern laws do not, and you may simply decline.
Black to move. En passant is usually a quiet little rule. Here it is the point of the position.
Show the answer
25.Kf1 25...Ba6+ 26.Bb5 26...Bxb5+ 27.c4 27...bxc3#
The line ends in checkmate. The position is from a real game on Lichess, rated 1097 in their puzzle pool, and it is one of the positions in the En Passant skill in the trainer.
Questions people ask
Is en passant a real rule?
Yes. It has been in the laws of chess for roughly five hundred years and it appears in article 3.7 of the current FIDE laws. Online platforms all implement it, which is where most players meet it for the first time, usually while losing a pawn to it.
Can you take en passant a move later?
No. The capture is only available on the move immediately after the two-square push. Play anything else and the right disappears permanently, even if the two pawns stay exactly where they are for the rest of the game.
Can a queen capture en passant?
No. Only a pawn can capture en passant, and only a pawn can be captured that way. Every other piece and every other capture in chess works normally.
Do you have to take en passant?
No. It is an option like any other capture. There are real positions where taking opens a file towards your own king or wrecks your pawn structure and declining is correct.
Why is it called en passant?
It is French for "in passing", which describes what happened: the pawn tried to pass yours, and you took it as it went by. Written down after a move it is often marked e.p., as in exd6 e.p.
Related
En passant sits under The special moves in the reference. Nearby: