En Passant

White tries and fails to sneak past the black pawn to a4
(the black pawn on b4 makes an “en passant” capture)

What is “en passant“?

En passant is a French term (pronounced quite like: “on passon”) meaning “In Passing”. It refers to a special pawn capture rule in chess which is possible in a certain special type of position.

The specifics are listed here:

1. One side has a pawn on it’s own 5th Rank

2. A pawn on a neighbouring file is still on it’s starting square

3. The pawn on the Starting square tries to sneak past the pawn on it’s 5th rank (to avoid getting captured)

4. If the player chooses, they can immediately capture the pawn that tried to sneak past their own pawn.

Note: You do NOT have to play the en passant capture if you do NOT want to.

But …. if you DO want to capture en passant, it MUST be on your NEXT move.

While en passant is an option you can choose to play or not play, this option disappears the moment you play some other move.

En passant captures need to be an immediate response to the attempt to sneak past a pawn by the pawn moving 2 squares from it’s starting square to it’s 4th rank.

By saying move “Immediately”, this does not mean “quickly“. It just means that if you want to play en passant, it needs to be your next move (whenever you decide upon that move). You cannot go back to it for a later move and then do an en passant capture.

Another En Passant example