Japan was ruled by warriors for the better part of a millennium. From the twelfth to the nineteenth century its political history was dominated by the struggle of competing leagues of fighting men. These centuries left a lasting imprint on the country's values and society. Bushi, “fighting men,” and samurai, “those who serve,” developed a rhetoric with emphases of loyalty and courage and worked out a code that came to be known as “Bushidō,” the Way of the Warrior. A stern and ruthless ethic had no tolerance for compromise or defeat. Honor to name and family counted for more than life, and failure permitted only one honorable exit, the grisly self-immolation of seppuku or, the more vulgar term, hara-kiri. Leaders attracted followings of “house men,” gokenin, who became in time their vassals and were entrusted with land and followers. The title of sei-i-tai-shōgun, “Supreme Commander Against the Barbarians,” which had been used as a temporary commission for frontier wars in northern Japan, became a hereditary term that signified the “head of the warrior houses,” buke no tōryō. It was vested successively in three lines, the Minamoto (1192–1333), Ashikaga (1333–1572), and Tokugawa (1605–1868).

The essays that follow, taken from volumes 3 and 4 of The Cambridge History of Japan, trace the institutional development of warrior rule and dominance. It is convenient to begin with the typology proposed by John W. Hall, who described a “familial” structure of rule that interacted with a more “imperial-bureaucratic” strain.