En passant explained simply

The phrase en passant is French for “in passing.” It describes a pawn capturing an opposing pawn while that pawn is considered to be passing through a threatened square. It is the only standard chess capture in which the captured piece is not on the capturing piece's destination square.

The rule in one sequence

Imagine that your White pawn has reached e5. Black then moves the pawn from d7 to d5, using its optional two-square first move. The Black pawn now stands directly beside your pawn. On White's very next move, the pawn on e5 may move diagonally to d6 and capture the Black pawn from d5. The final position is exactly what it would have been if Black had moved only from d7 to d6 and White had captured on d6.

For Black, the pattern is reversed. If a Black pawn is on e4 and a White pawn advances from d2 to d4, Black may immediately play from e4 to d3 and remove the White pawn from d4.

Every condition that must be true

An en passant capture is legal only when all of these conditions are satisfied:

• The capturing piece is a pawn.
• The opposing pawn has just advanced two squares from its starting square.
• That two-square move places the opposing pawn directly beside your pawn on the same rank.
• Your pawn attacks the square the opposing pawn crossed.
• You make the capture immediately, on the very next move.
• The move does not leave your own king in check.

If you choose any other move, the en passant opportunity expires. It does not return on a later turn. The two pawns might remain side by side, but they can no longer use this special capture against each other.

Why does en passant exist?

Historically, pawns gained the option to move two squares from their starting position to speed up the opening. Without en passant, a pawn could use that leap to pass a square controlled by an advanced enemy pawn and avoid a capture that would have been possible after a one-square move. En passant preserves the advanced pawn's control for one turn.

The rule is therefore not an exception without a purpose. It balances the convenience of the initial two-square move. The opposing pawn can treat the move as though it crossed the attacked square one step at a time.

Check and pinned pawns

Like every move, en passant must leave your king safe. This matters because removing two pawns from their original squares can open a rank, file, or diagonal. Suppose your king and an enemy rook face each other along a rank, with the two pawns currently blocking the line. An en passant capture might remove both blockers from that line and expose your king. In that case, the capture is illegal.

En passant can also be the correct response to a checking move, or it can deliver discovered check, but only if the resulting position obeys the normal king-safety rules. Do not judge legality from pawn movement alone; inspect the entire board after the capture.

Notation and common misunderstandings

In algebraic notation, en passant is written like an ordinary pawn capture: the pawn's starting file, the letter “x,” and the destination square. In the first example, White's move is exd6. Some explanatory scores add “e.p.” afterward, but that suffix is optional.

A pawn cannot capture en passant after an opposing pawn moves only one square. It also cannot capture a knight, bishop, rook, queen, or king this way. The rule applies only to a pawn's immediate two-square move from its original rank. Nor may your pawn capture into the square where the opposing pawn finished; it moves to the crossed square and removes the adjacent pawn.

Should you always capture?

En passant is optional. Before using it, evaluate the resulting pawn structure. The capture might create a passed pawn, open a file for a rook, gain space, or prevent an enemy pawn from becoming dangerous. It might also pull your pawn away from defending an important square or open a line that benefits your opponent.

Because the right expires immediately, compare the capture with your other candidate moves before deciding. There is no later opportunity to reconsider. In a browser game, legal-move indicators may help you notice the option, but knowing the rule lets you understand why it appears.

A quick way to remember it

Look for two pawns standing side by side immediately after one has advanced two squares. If the other pawn could have captured it had it moved only one square, en passant may be available now. Then perform the final safety check for your king.

See the complete chess rules guide for every other move and game-ending condition. To learn the other move with especially detailed restrictions, read how castling works.