Holy hell. It's real, it's legal, and it has been ambushing people since the 1400s. Don't just take our word for it: the board below is live, and that d-pawn is about to get cocky.
French for “in passing.” Pronounced roughly on pah-SONT.
When an enemy pawn advances two squares from its starting rank and lands directly beside your pawn, you may capture it as if it had only moved one square: your pawn steps diagonally into the square it skipped, and the enemy pawn comes off the board. One catch. The right expires immediately: use it on the very next move, or lose it forever.
It's the only capture in chess where the capturing piece doesn't land on the captured piece's square — which is exactly why it looks illegal the first time someone plays it against you.
En passant is codified in Article 3.7 of the FIDE Laws of Chess. It is legal in every rated game on Earth.
For most of chess history, pawns could only ever crawl one square at a time. The two-square first move arrived in the late Middle Ages, part of the same wave of speed-ups that gave the queen her modern powers. Openings were agonizingly slow, and everyone knew it.
But the shortcut created a loophole: a pawn could use its double-step to sneak past an enemy pawn's control square without ever being capturable. Players considered this cheating the spirit of the game, so the fix arrived with the shortcut. Pass a pawn like that, and it may be taken as if it had moved one square. In passing. En passant.
Adoption wasn't instant. Italian players kept the pass-through legal for centuries (they called it passar battaglia, “passing through battle”), and the rule only became truly universal in the 1880s. Which means chess players have been arguing about en passant for roughly four hundred years. You're in good company.
En passant is rare enough that millions of people reach their first suspicious-looking encounter believing their opponent is cheating. On r/AnarchyChess, the traditional reply to anyone who doubts the rule is simply: “google en passant.” The traditional response upon learning the truth is “holy hell.” The chain continues from there (new response just dropped, actual zombie, call the exorcist…) and has outlived several governments.
Two more pieces of jurisprudence you should know: in r/AnarchyChess law — though not in FIDE law — en passant is forced, and refusing to play it carries a penalty involving a brick. We don't make the rules. (We just host them.)
Yes. FIDE Laws of Chess, Article 3.7. Legal on Chess.com, on Lichess, in your local club, and in the World Championship. Your opponent was not cheating. Sorry.
In real chess, no — it's optional like any capture, unless it happens to be your only legal move. In r/AnarchyChess jurisprudence, yes, always, on pain of brick.
No. It's strictly pawn-takes-pawn: only a pawn that just double-stepped can be captured, and only by an enemy pawn directly beside its landing square. No queens, no knights, and — despite what the memes say — no kings.
Three conditions: your pawn is on its fifth rank; an enemy pawn double-steps from its starting square and lands directly beside it; and you capture immediately — the very next move, or never.
Like any pawn capture, naming the landing square: exd6. Writers sometimes add “e.p.” for clarity — exd6 e.p. — but it's optional.
Database counts put an actual en passant capture in only a few percent of games — but the opportunity comes up far more often. Most players never notice it. Which brings us to…
Somewhere in your games, a pawn double-stepped past you and got away with it. Or the chance was there and you played something quieter. Elo Hell runs a full engine review of any Chess.com or Lichess game: every mistake explained in plain English, free, no account.