The Book of Five Rings is a classic Japanese text by the undefeated swordsman Miyamoto Musashi. Shortly before his death in 1645, Musashi retreated to a cave to live as a hermit. There he wrote five scrolls describing the 'true principles' required for victory in the martial arts and on the battlefield. Instead of relying on religion or theory, Musashi based his writings on his own experience, observation, and reason.
Miyamoto Musashi