History of the Martial Art
Instead of running the risk of losing himself in the complicated genealogy of the numerous schools of iia, let us say rather that, from the very day on which the first saber was forged, the warrior became interested in the art of drawing. The specificity of the Japanese warrior in this art rests on the following observation: there is practically no shield in the whole martial history of Japan. The saber has only one sharp side, and the guard is so small that its role is less to protect the arm than to balance the saber. As a result, the Japanese warrior, disregarding any cumbersome protection, finds himself obliged to compensate for this lack of security by a foolproof technique.
The iai concerns only the disengagement which is done according to the principle of kôbo-ichi (attack and protection are only one). In other words, the warrior draws his saber only to cut in the same movement, and this from any position in any direction. Everything is there.
The various schools of science competed with ingenuity to refine and improve these techniques of dragging, where rapidity is translated not by speed but by sobriety of movement and the "right moment" chosen to do so.
The most popular tradition in Japan is that of Musô Shinden Ryû, founded by Hayashizaki Jinsuke Shigenobu. It is composed of simple but extremely educational movements. Other traditions, more martial, can then be approached by the practitioner trained at this first school.