En passant is a special rule in chess that allows pawns to capture an opposing pawn that has just moved two squares forward from its starting position and landed next to the capturing pawn on an adjacent file. This move is only available on the next turn after the opposing pawn has made its two-square move, and only if the capturing pawn is on its fifth rank. The en passant capture is the only capturing move in chess where the capturing piece moves to a square not occupied by the captured piece. Only pawns may capture or be captured en passant. The en passant capture is often used as a theme in chess problems.