Ginoza curveball
The “Ginoza Curve” is named after Ginoza High School in Okinawa Prefecture, where it was first developed.
It is a variation of the 12-6 (vertical) curveball and is thrown with aggressive wrist rotation at release to generate extreme topspin.
Because of its mechanics, it is generally considered a pitch that can only be thrown from an overhand delivery.
While a shuto uses a natural inward rotation to let the ball roll off the fingers, the Ginoza Curve uses inward rotation to actively generate spin.
At release, the force of the throw—amplified by centrifugal force—places significant stress on the elbow, particularly on the tendons that are heavily twisted during the motion.
Because of this, there is a high risk of serious injury.
For this reason, the author has chosen not to pursue further development of this pitch.
Please note that some of the explanations here are based on observation and estimation rather than definitive scientific analysis.
Take this into consideration when deciding whether to practice or attempt this pitch.
Grip and Release
The grip is the same as a standard curveball.
If you want to generate stronger spin, you may place the fingertips of your index and middle fingers more firmly along the seams.
Since wrist action plays a major role in generating spin, it is important to be conscious of seam placement when gripping the ball.
From a position where the back of the hand is fully facing the catcher, the wrist is forcefully rotated inward to outward—more than 180 degrees—at release.
This motion requires a very loose and flexible arm.
Excess tension will prevent smooth movement and significantly increase the risk of injury.
Proper flexibility, especially around the elbow, is essential.
Thorough stretching and mobility work may help reduce the risk of injury.
This pitch involves an extreme and unnatural motion that can place heavy stress on the arm.
Carefully consider the risks before attempting to learn or use this pitch.