En passant
En passant is a pawn capture. If an enemy pawn moves two squares and lands beside your pawn, you may capture it as if it had moved one square. You can do this only on the next move.
The capture is legal only for pawns, only immediately after the two-square move, and only when your pawn stands on the fifth rank (for White) or the fourth rank (for Black).
You capture onto the square the enemy pawn passed over, not onto the square it landed on. The enemy pawn is removed from the board.
If you play another move first, the chance is gone. You do not have to capture.
On the board
8
7
6
5
4
3
2
a1
b
c
d
e
f
g
h
White to move. The black pawn has just played d7-d5, beside the white pawn on e5. Capture it en passant.
Common mistakes
- Capturing en passant a move later. The right exists for one move only.
- Thinking a piece other than a pawn can take en passant. Only a pawn can.
- Taking on the square the pawn moved to, the way a normal capture works. The capture square is the one in between.