Real-life figure Miyamoto Musashi was the most celebrated samurai of all time. The quintessential warrior philosopher, Musashi authored A Book of Five Rings, a theoretical guide to military strategy still used today by modern-day businessmen. But the path to enlightenment in feudal era Japan was fraught with peril. At 17 years of age, Musashi - still known by his childhood name Shinmen Takezo - was a wild young brute just setting out along the way of the sword.