Aiki (martial arts principle) and its practice is often kept within a particular individual or two from a family/school lineage. Culturally, and due to certain necessities of the time period, the aiki knowledge was usually a very well guarded secret and rarely disclosed. The oldest book to have historically discuss aiki was the 1899 Budo Hiketsu-Aiki no Jutsu. On the subject of aiki it was written: The Textbook of Jujutsu (Jujutsu Kyoju-sho Ryu no Maki) from 1913 wrote: Aiki (martial arts principle) Aiki from a Japanese budo term, at its most basic is a principle that allows a conditioned practitioner to negate or redirect
Budo: The Art of Killing sword cuts including a shot filmed in slo-motion showing the shocking speed in which a Japanese sword can behead a man (1/100 of a second). Continuing with a focus on the sword, the film shows the art of traditional nihonto forging by swordsmith Amada Akitsugu, considered a national living treasure in Japan. "Budo: The Art of Killing" concludes with scenes of Noh as the narrator explains, "As long as the universal truths of heaven, the earth and man remain, the spirit of Budo shall endure." Hisao Masuda had no luck trying to find financing for "Budo: Art of Killing" in