OK, one point I did not see mentioned is the Instant Center, the EFFECTIVE center of mass of the moving system of sword, arm and body. You know this instinctually when swinging a baseball bat and hit the ball and feel nothing at your hands. Yes, I know purest's abhor discussion of katanas and baseball bats, but its an analogy.
What this means is that the entire system of the cut with a sword boils down to speed, rotation, technique, sword center of mass based on distribution, the user physiology, etc, etc. What is boild down to is that during a PERFECT cut, the users feels essentually nothing, all the force is at the cutting surface, and the cut is effortless as the sword transfers all its energy through the cut. Approximately 60-70% down the length of the katana, if done properly. And since the katana cuts best in a slightly drawn cut, this live center follows the cut through the body in a gentle arc starting at the 60% poiint and sweeps back to the 70% point.
Thats the mechanics, perfect practice assures perfect execution, so to speak.
Larry
Tinkerer
What this means is that the entire system of the cut with a sword boils down to speed, rotation, technique, sword center of mass based on distribution, the user physiology, etc, etc. What is boild down to is that during a PERFECT cut, the users feels essentually nothing, all the force is at the cutting surface, and the cut is effortless as the sword transfers all its energy through the cut. Approximately 60-70% down the length of the katana, if done properly. And since the katana cuts best in a slightly drawn cut, this live center follows the cut through the body in a gentle arc starting at the 60% poiint and sweeps back to the 70% point.
Thats the mechanics, perfect practice assures perfect execution, so to speak.
Larry
Tinkerer