Yagyū Jūbei Mitsuyoshi (柳生 十兵衞 三厳, 1607 – April 12, 1650) was one of the most famous and romanticized of the samurai in Japan's feudal era.
Very little is known about the actual life of Yagyū Mitsuyoshi as the official records of his life are very sparse. Yagyū Jūbei Mitsuyoshi (born "Shichirō") grew up in his family's ancestral lands, Yagyū no Sato, now in Nara. He was the son of Yagyū Tajima no Kami Munenori, master swordsman of the Tokugawa Shoguns, especially Ieyasu and Tokugawa Iemitsu, who prized Munenori as one of his top counselors.
Munenori fought for the first Tokugawa shogun, Tokugawa Ieyasu, at the Battle of Sekigahara, expanding the Shogun's territory. For his efforts, Munenori was made the Shogun's sword instructor and a minor daimyō (provincial ruler), by extending his family hereditary domain up to 10,000 koku. Despite not being the heir of his father as the headmaster of the Yagyū style (and thus far from being an unrivaled swordsman under the Heaven), he received the post for its importance in Japanese politics and Court intrigues, at which Munenori was better than the other members of his clan. Munenori would go on to train three successive Shoguns: Ieyasu, Hidetada, and Iemitsu.
In 1616, Mitsuyoshi became an attendant in the court of the second Tokugawa Shōgun, Tokugawa Hidetada and became a sword instructor for the third Tokugawa Shōgun, Tokugawa Iemitsu, occasionally filling his father's role. Records of Yagyū Jūbei Mitsuyoshi, however, do not appear again until 1631, when Jūbei, by now regarded as the best swordsman from the Yagyū clan, is summarily and inexplicably dismissed by the Shōgun either due to Jūbei's boldness and brashness or his decision to embark on a Warrior's Pilgrimage (武者修行, Musha Shugyō).