Seam bowling is a technique in cricket where the ball is deliberately bowled on its seam to cause a random deviation when the ball bounces. The seam of the ball is the circular stitching that joins the two halves of the cricket ball, and it is noticeably raised. If the ball is bowled in such a way that the seam hits the pitch when it bounces, this irregularity can cause the ball to deviate sideways in its path. The batsman has to see how the ball moves after pitching to select his shot. To achieve this effect, a seam bowler usually delivers the ball with the seam held upright, with rotation about a horizontal axis. Seam movement is a sharp movement caused by the seam of the ball hitting imperfections in the pitch. Seam bowling is different from swing bowling, which relies on movement in the air due to a difference in airflow on either side of the seam.