From the Translator's Introduction

The Book of Five Rings and The Book of Family Traditions on the Art of War are two of the most important texts on conflict and strategy emerging from the Japanese warrior culture. Originally written not only for men-at-arms, they are explicitly intended to symbolize processes of struggle and mastery in all concerns and walks of life.

The Book of Five Rings was written in 1643 by Miyamoto Musashi, undefeated dueler, masterless samurai, and independent teacher. The Book of Family Traditions on the Art of War was written in 1632 by Yagyu Munenori, victorious warrior, mentor of the Shogun, and head of the Secret Service.

Both authors were professional men-at-arms born into a long tradition of martial culture that had ultimately come to dominate the entire body of Japanese polity and society. Their writings are relevant not only to members of the ruling military caste, but also to leaders in other professions, as well as people in search of individual mastery in whatever their chosen path.

The Book of Five Rings and The Book of Family Traditions on the Art of War are both written in Japanese, rather than the literary Chinese customary in elite bureaucratic, religious, and intellectual circles in Japan at that time. The Japanese in which they are written, furthermore, is relatively uncomplicated and quite free of the subtle complexities of classical high court Japanese. Although the crudity of Musashi's syntax and morphology make for clumsy reading, nevertheless the basic simplicity and deliberate clarity of both works make them accessible to a wide and varied audience.

The rise and empowerment of the samurai class in Japan may be seen in the two terms used to refer to its members, samurai and bushi. The word samurai comes from the Japanese verb saburau, which means "to serve as an attendant." The word bushi is Sino-Japanese and means "armed gentry." The word samurai was used by other social classes, while the warriors referred to themselves by the more dignified term bushi.

The original samurai were attendants of nobles. In time their functions expanded to the administration, policing, and defense of the vast estates of the nobles, who were mostly absentee landlords. Eventually the samurai demanded and won a greater share of the wealth and political power that the nobles had called their own. Ultimately the military paragovernment of the Shoguns, known as the Bakufu, or Tent Government, overshadowed the imperial organization and dominated the whole country.

Musashi and Yagyu lived in the founding era of the third Tent Government, which lasted from the beginning of the seventeenth century through the middle of the nineteenth century. While inheriting the martial traditions of its predecessors, this third Tent Government differed notably in certain respects.

The first Tent Government was established in eastern Japan near the end of the twelfth century and lasted for nearly one hundred and fifty years. The warriors of this time were descendants of noble houses, many of whom had honed their martial skills for generations in warfare against the Ainu people in eastern Japan. As the Tent Government was seated in Kamakura, a small town near modern Tokyo, this period of Japanese history is commonly called the Kamakura era.

The second Tent Government supplanted the First in 1338. The warrior class had expanded and become more differentiated by this time, with lesser and thinner genealogical ties to the ancient aristocracy. The Shoguns of this period established their Tent Government in...