What Is En Passant in Chess? Learn About the Special Pawn Capture and Its Uses

En passant is a special rule that allows pawns to capture pawns on adjacent tiles under special circumstances. According to FIDE, the governing body of chess, the rule goes like this:

“A pawn attacking a square crossed by an opponent’s pawn which has advanced two squares in one move from its original square may capture this opponent’s pawn as though the latter had been moved only one square. This capture is only legal on the move following this advance and is called an ‘en passant’ capture.”

That’s a pretty dry description, but here’s what it means in the context of a hypothetical game:

1. 1. Say you’re playing white, and you move your e-pawn forward three ranks over the course of the game, so that you’re now on the 5th rank, e5.
2. 2. Then, let’s say black has not moved either her d- or her f-pawn (the pawns on adjacent files) forward yet. She decides to bring her d-pawn forward two steps from its starting square, so that it’s now on d5, directly adjacent to your e5 pawn.
3. 3. Now, on this next move, you have the opportunity to capture black’s d-pawn as though it were on d6. If you take the move, you’ll take black’s pawn, and your pawn will finish on d6.

It’s important to note that is special capture is only legal right after the opponent makes the two-step move. If you don’t capture en passant then, you’ve lost your chance (at least with that particular pawn).

Where does this seemingly strange rule come from? Its origins go back to Europe in the fifteenth century, when the modern rules of chess were being finalized. Specifically, it evolved as a response to the introduction of the initial double-step for pawns, which itself was an innovation designed to speed up the game.

The double-step introduced a complication, however. A pawn that could move forward two spaces at once could evade the risk of capture by an opposing pawn on an adjacent file that had already advanced to the 5th rank (4th for black). This put the player who’d studiously advanced her pawns at a disadvantage.

Thus, en passant was introduced to give players a player who’s advanced a single chance to take a pawn that might otherwise be uncapturable.

Say black moves her b-pawn forward twice, so that they’re now on b4. Now white moves her c-pawn forward two steps to c4. Black now has the opportunity to capture en passant. On this turn only (the turn after the two-step move has taken place), black may move her pawn on b4 to c3, capturing white’s c4 pawn in the process.

In chess notation, this would be written as:

1. 1. … b4
2. 2. c4 bxc3!

A few things to reiterate:

1. 1. Because en passant can only occur after an opposing pawn has moved two steps forward, as a general rule pawns may only capture en passant on the 5th rank (for white) or the 4th (for black).
2. 2. Again, en passant is only legal the turn the two-step advance is made. If you don’t perform the capture on that turn, you forfeit the right to do it, unless it comes up again on a different file.

Though it’s relatively rare in practice, en passant (or at least the threat of it) can be an important tool in your opening or endgame strategy. But as with any move in chess, it’s important to evaluate your entire position.

En passant can be a great way to advance a pawn you plan to promote, but if that same pawn is the linchpin in your position, moving it off its file could cause your whole strategy to collapse. Just because it’s rare and in the rules of chess doesn’t mean en passant is always the strongest move.

That said, it’s an important rule to be aware of, if only so that a canny opponent doesn’t catch you unaware.

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