In American and Canadian football, a line of scrimmage is an imaginary transverse line (across the width of the football field) beyond which a team cannot cross until the next play has begun. Its location is based on the spot where the ball is placed after the end of the most recent play and following the assessment of any penalty yards. In Canadian football, the team on defense must line up no nearer than a yard to the line of scrimmage. In American football, they must only be beyond the line.