Gripping The Sword

The purpose of the grip is produce maximum leverage when deploying the sword. Therefore, careful consideration is given to the placement of his/her hand on the hilt (handle) of the sword:

The hands are placed widely apart, as far as the handle can accommodate.
The left hand must grip the very end of the butt of the handle. The little finger can project beyond the butt.
The right is positioned on the handle about the width of a finger from the hand-guard
The web space the thumb and the index finger or the “V” formed by the thumb and index finger must be positioned directly over the back of the handle of the sword.
The thumbs must more or less point toward the floor.
There should be a golf ball-size space between the right hand and the guard. The thumb of the right hand should not touch the guard. However, the index finger may.
The base of the thumbs in relationship to the wrist, the anatomical snuff box, must also form a “V” and not be rounded. Keep in mind, always a “valley”, never a “peak”.
Proper grip will allow the pressure of a cut to conduct up the arms while recruiting the brachio-radialis, bicep brachii, pectoralis minor and major and the latissimus dorsi which is critical to mechanically drive the sword from a high to low vertical plane. Whereas, an incorrect (base ball) grip will cause weakness across the thumbs and recruit arm adductors such as the middle deltoid which is counter productive.
When cutting, the left hand provides the power, the right hand guides the sword.