en passant

En passant is a special capture between pawns. It becomes possible when an opposing pawn uses its initial two-square advance and finishes beside a pawn that could have captured it if it had moved only one square.

Conditions

• The opponent's last move must have advanced that pawn two squares from its starting square.
• The pawn must finish in the adjacent vertical column and on the same horizontal row as the capturing pawn.
• The capture is available only on the immediately following move. Choosing another move makes the right disappear.

Using standard square names, formed by a column letter and a row number, the move can look like this: if a white pawn is on e5 and a black pawn has just moved from d7 to d5, White may move the pawn from e5 to d6 and remove the pawn from d5, provided White's king remains safe.

The capture remains subject to every normal legality rule. It cannot be played if it leaves the capturing side's king in check. The French phrase en passant means in passing, because the pawn is taken as if it had not been allowed to pass the opposing pawn completely in one move.