How to make an "Iron Fist"

Referring back to point 8 ,even when one can't see one's opponent, one must train one's hands and fingers so that it is possible to attack through things.This is called "Tesasho". When people want to study tenketsu, they start training Tesasho to train the edges of their bodies such as the fingers.

This idea has its origions from centuries ago "When a fist is strengthened it should be so hard that it can break a tigers head, and your knife hand should break the cow's neck.."

Asai Sensei believes that this is going too far, but through this training, Asai Sensei has been able to break iron bars with his fingers. Therefore, using the "iron fist" against the 36 deadly pressure points is very destructive indeed.