Iizasa Chōisai

Iizasa Chōisai (1387–1488) was a legendary martial strategist born near the sacred precincts of Katori Shrine in Shimōsa Province (present-day Chiba Prefecture), who founded "Tenshin Shōden Shintō-ryū (Katori Shintō-ryū)" and is known as the founder of Japan's oldest existing martial arts school. Said to have lived to 102, he is believed to have attained divinely-inspired swordsmanship through rigorous training in the shrine's sacred precincts.

After participating as a warrior in various conflicts throughout the Kantō region, Chōisai is said to have entered a 1,000-day period of training in the sacred precincts of Katori Shrine past the age of 50. During this training, he received an oracle from the Great Deity of Katori (the war god Futsunushi-no-kami) and was granted the inner teachings of swordsmanship. This experience of divine transmission is the origin of the name "Tenshin Shōden Shintō-ryū," demonstrating that swordsmanship had become connected to a Shintō spirituality transcending mere combat technique.

Tenshin Shōden Shintō-ryū was established as a "comprehensive military strategy" systematizing all aspects of martial arts—not just swordsmanship but also spear techniques, naginata, jujutsu, shuriken, archery, and military science. It maintains a dojo near Katori Shrine in Narita City, Chiba Prefecture today, attracting worldwide attention as the oldest existing martial arts school with movements seeking UNESCO Intangible Cultural Heritage registration.

From Chōisai's lineage emerged many swordsmen, including Matsumoto Bizen-no-kami, who exerted great influence on the later Kashima and Katori traditions of swordsmanship. The various schools formed by these disciples eventually created the major currents of Japanese swordsmanship, and Chōisai is revered as the "ancestor of Japanese swordsmanship." In his relationship with swords, the Shintō-ryū tradition of treating the sword as a sacred implement and honoring the spirituality of the way of the sword is inherited to this day.