This classic samurai-era text fused Japanese swordsmanship with Zen and influenced the direction that the art has taken ever since. Written by the seventeenth-century Zen master Takuan Soho (1573-1645), The Unfettered Mind is a book of advice on swordsmanship and the cultivation of right mind and intention. It was written as a guide for the samurai Yagyu Munenori, who was a great swordsman and rival to the legendary Miyamoto Musashi.

Takuan was a giant in the history of Zen; he was also a gardener, calligrapher, poet, author, adviser to samurai and shoguns, and a pivotal figure in...