En passant is a pawn technique that most beginners do not know of. If they play someone expreicenced, sometimes they call it "cheating". En passant is when a pawn passes an opposing pawn to try to "escape" the pawn by moving two spaces up. The position will be a white pawn next to a black pawn. Next, white can move diagnally as if the black pawn was there (but it isn't) and take the black pawn. En passant can only happen if the situation explained happens. Nothing else.