名取正澄

Natori Masazumi (dates disputed, traditionally c.1603–1708) is the author of the Shōninki, written in 1672 and regarded by scholars as the most philosophically sophisticated of the surviving ninjutsu manuals. Unlike technical handbooks that catalog methods and equipment, Shōninki is a work of moral and spiritual philosophy, integrating Buddhist, Daoist, and Confucian thought into a coherent theory of the 'way of the shinobi.' What makes Masazumi especially relevant to the history of swordsmanship is his insistence that ninjutsu and kenjutsu are not separate arts but dimensions of a unified martial cultivation. The superior shinobi, he argues, must also be a superior swordsman; and the mental discipline cultivated in swordsmanship — composure, perceptual clarity, the ability to read an opponent before the blade moves — is foundational to the shinobi's work. He develops a concept of 'the sword of the mind' (kokoro no ken): the capacity to dominate a situation without drawing steel. This idea resonates closely with the Yagyū Shinkage-ryū concept of the 'sword that gives life' (katsujin-ken). Masazumi served in service related to the Kii Tokugawa branch — one of the Three Lords of the Tokugawa house — and operated in a regional sword culture that included Kii-tradition smiths working under Tokugawa patronage. His synthesis of the philosophical and the practical makes him one of the most important martial theorists of the early Edo period.