Yamaoka Tesshu was a great Zen layman, master calligrapher, swordsman and statesman of the Meiji Restoration era in Japanese history. Tesshu was a genius in several areas of life. He was considered one of the greatest swordsmen of his time, the headmaster of two branches of the Itto Ryu style and founder of the Muto Ryu style of swordsmanship.
He was also considered one of the top calligraphers of the time, and his calligraphy fetched so much money that Tesshu's many creditors often preferred to hold on to his IOUs rather than cash them in- the IOUs written by Tesshu's brush were actually worth more than what he owed them!
Tesshu was involved in the transition of power from the Tokugawa shogunate to emperor Meiji, and is credited with negotiating with the Meiji forces to spare Tokyo from destruction. He later went on to work for the new emperor himself. Because he had worked for both sides- although for patriotic reasons- there were fanatics on both sides who wanted him dead. Tesshu survived several assassination attempts without harming his assailants, and some of them went on to become his students. In fact, despite engaging in several duels with sharp swords, Tesshu never killed a man in all his battles.
Along with his many other achievements, Tesshu achieved enlightenment in Zen Buddhism, using his memories of a particularly tough opponent as his own personal koan or Zen riddle. Tesshu, however, was no saint- he seems to have been an alcoholic and what we now think of as a sex addict, spending much of his time in the pleasure quarters when he wasn't sword-fighting, doing calligraphy or working for the emperor. Tesshu is one of those rare examples of an undeniably flawed but still incredibly impressive human being.