12–6 curveball

[2] The 12 to 6 curveball is usually pitched from the overhand motion, as a three-quarters or sidearm delivery would cause the ball to break 2 to 8 instead of 12 to 6.

[2] The sharp vertical break on the 12–6 curveball is created when pitchers apply topspin to the ball with their fingers in the process of releasing it.

[1] The effectiveness of the pitch also depends on the ability of the pitcher to apply topspin to the ball, creating movement.

When stats for a high level pitcher's average 12 to 6 curveball are factored in, the 12 to 6 and the 11 to 5 are much more effective than Major League Baseball's average throwers of the pitch due to the pitcher's high level of ability for that pitch.

This grip allows the pitcher to create a high amount of topspin while still having a good control of the pitch.