A Japanese sword is designed to slice. An ax is designed to chop. The mass and balance of a sword is designed to slice at the tip, instead of chopping near the hands. Since this is the case, a sword’s tip should move along the greatest arc from a center point. By applying the principles of math, the longer the radius of a circle, the longer the arc. If the sword takes the same amount of time to travel a greater distance, greater radius=greater circumference, then the sword is moving faster with the greater distance.
A swordsman contributes his mass to the mass of the sword to increase the penetration of the cut. The strongest part of a human’s body is the hips and center, which means if we integrate our center into the cut, we are able have greater penetration and a larger radius. By cutting from our centers we employ both of these principles to create a more powerful cut. Keep training!
Iaido Tanshinjuku 