[1][2] He became a Zen Buddhist priest and relayed his experiences, memories, lessons, ideas, and aphorisms to the samurai Tashiro Tsuramoto [ja], who compiled them under the title Hagakure.

[3] In his twenties, Tsunetomo studied under the Zen Buddhist priest Tannen and the Confucian scholar Ishida Ittei, both of whom greatly influenced his philosophy.

[5] In 1695, Mitsushige retired due to ill health, and tasked Tsunetomo with finding a copy of a book of secret poetry instructions called Kokindenju.

Instead of continuing as a samurai seeking minor positions, Tsunetomo became a Buddhist priest and his wife became a nun, living in a hermitage in the mountains.

Some viewed him as a man of immediate action due to some of his quotes, and in the Hagakure he criticized the carefully planned Akō vendetta of the Forty-seven rōnin (a major event in his lifetime) for its delayed response.