Yamaga Sokô is without doubt one of the most important figures in the history of bushido.  A rônin (masterless samurai) during the Tokugawa period, Sokô’s most significant contributions were codifying the bushido ethic and re-envisioning the role of the samurai.  His systematic articulation of the samurai spirit helped provide a philosophical basis for bushido.  Sokô detested the teachings of the Sung neo-Confucian school and the sense of spirituality it tried to instill into Confucianism.  He was, nonetheless, heavily influenced by Confucian teachings.

Sokô viewed devotion to duty as the most important aspect of a samurai’s life and believed that the samurai class should assume moral leadership in society.  In this sense he helped redefine the samurai’s role in the Pax Tokugawa and gave the warriors a new raison d’etre.  His work reflects prevailing notions during his time that the samurai should combine intense martial training (bu) with high intellectual pursuits (bun).  In addition, Sokô’s devotion to the imperial house later helped justify the overthrow of the shogunate during the Meiji Restoration.

English Translations
There are relatively few English translations of Yamaga Sokô’s works.  The one listed below is an excerpt from his work Shidô.

The Way of the Samurai, in Sources of Japanese Tradition, Volume I (New York: Columbia University Press, 1958), pp. 389-91