The Book of Five Rings by Miyamoto Musashi

In the early seventeenth century, one warlord surpassed all others in prominence - Tokugawa Ieyasu. In 1603, Ieyasu established a centralized state with its capital in Edo, which is present-day Tokyo. He achieved a feat that no other shogun had accomplished before - the disarmament of his adversaries. Potential usurpers were compelled to reduce the size of their warrior contingents.