Tengu Art Theory "Two" This is an old book. It is likely a single volume from a set of four volumes. This is "Two" only. Tengu Art Theory is an Edo-period didactic book written by Issai Chozan, who is considered the progenitor of didactic books that were popular in the mid-Edo period, blending humor with moral lessons and satire. The content can be described as a swordsmanship book that discusses the spiritual aspect, focusing on the nature of "ki" (spirit/energy), "kokoro" (mind/heart), and "do" (way/path). A swordsman encounters a Tengu in the deep mountains, and through a blend of Taoist, Confucian (Confucius and Mencius), and Buddhist thought, touches upon the core of "art," meaning "martial arts" and "mind techniques." There are no noticeable scratches, dirt, or tears, but please understand that this is an old book before considering your purchase. 226217