Traditionally, a club face is polished horizontally, but avoiding the trap of conventional wisdom, Yonex has adopted a vertical polish. A design that eliminates the need for grooves on the face, improving shot direction and minimizing side spin.
With a vertical polish it is easier to move the ball in an upwards direction rather than horizontally. As a result, the spin axis is difficult to change and destructive side spin is minimised.
With horizontal polishing it is easier to move the ball in a left/right direction compared to vertical polishing. As a result, the spin axis tilts, and there is an increase in side spin.
Vertical polishing improves accuracy by decreasing side spin. Testing shows a difference of up to 5 yards.