If you've ever had someone accuse you of cheating after you captured a pawn that "wasn't even in the way," you've met en passant — a completely legal, official chess rule that somehow remains the single most disputed move in the game, even among players who've played for years.
What en passant actually is
En passant ("in passing," French) is a special pawn capture that can happen right after an opponent's pawn moves two squares forward from its starting position, landing beside one of your pawns. Normally, a pawn only captures diagonally into a square it's moving to — en passant is the one exception where a pawn can capture a piece that didn't land on the square it's capturing into.
Here's the exact sequence:
- An opponent's pawn, still on its starting rank, moves two squares forward in one move (using the pawn's standard first-move option).
- That two-square move lands the pawn directly beside one of your pawns — same rank, adjacent file.
- On your very next move only, your pawn can capture that opposing pawn as if it had only moved one square — your pawn moves diagonally into the square the opponent's pawn passed over, and their pawn is removed from the board.
If you don't take the capture on that immediate next move, the option disappears permanently for that pawn — you can't come back to it three moves later.
Why it feels like it shouldn't be legal
Visually, it looks wrong: your pawn ends up on an empty square, and a completely different square's piece disappears. Every other capture in chess involves moving onto the exact square the captured piece occupies — en passant is the only move in the entire game that doesn't work that way, which is exactly why it trips people up so consistently, including plenty of players well past the beginner stage.
Why the rule exists at all
This isn't an arbitrary exception — it's a patch for a different rule change. Originally, pawns could only ever move one square at a time, even on their first move. The two-square first move was added later specifically to speed the opening phase of the game up. But that change created a loophole: a pawn could now "sprint past" an enemy pawn that was poised to capture it one square at a time, completely avoiding a capture it would otherwise have been exposed to. En passant closes that loophole — it preserves the capturing chances a pawn would have had under the old one-square-only rule, even after the two-square move was introduced.
A concrete example
Say your pawn sits on e5. Your opponent, still holding their pawn on its starting square at f7, pushes it two squares to f5 — landing it directly beside your e5 pawn. On your very next move, you can play exf6: your pawn captures diagonally onto f6 (the square the opponent's pawn passed over), and their pawn on f5 is removed from the board, even though your pawn never touched f5 itself.
Wait even one move — play something else first — and that specific capture is gone for good, even though the opposing pawn is still sitting right there on f5.
Quick reference: is en passant legal here?
- ✅ Opponent's pawn just moved two squares from its starting rank, this move
- ✅ It landed directly beside your pawn (same rank, adjacent file)
- ✅ You're capturing on your very next move
- ❌ Any other pawn move by them (a one-square move, or a two-square move from earlier in the game) — not eligible
- ❌ You waited a move before capturing — the window has closed
Frequently asked questions
Is en passant an optional rule, like a house rule? No — it's an official rule in the standard laws of chess, used identically in every FIDE-rated tournament and every legitimate online chess platform, including here. It's never optional or platform-specific.
Can en passant happen with any piece, or just pawns? Only pawns. It's a pawn-specific exception that exists solely because of the two-square pawn first-move rule.
Why does it feel like nobody uses it? The exact conditions (a two-square pawn move landing beside your pawn, captured immediately) don't come up in every game, so it's genuinely less frequent than other captures — but it's not rare enough to be a trick move; strong players watch for it constantly in the opening and early middlegame.
What happens if I miss the one-move window to capture? Nothing special — the capturing option simply disappears for that specific pawn. The opposing pawn stays on the board and can be captured normally later if the position allows it, just not via en passant anymore.
Want to see it in action rather than just read about it? Push a pawn two squares next to an AI-controlled pawn in a game against the AI and watch for the capture window — or walk through it slowly with a friend in a local game.