“bushido: Jap, ‘way of the warrior’) At first an unwritten code of ethics, devised for the moral and spiritual guidance of the entire military class by military leaders during the Kamakura period, bushido was codified during the Tokugawa regime. Emphasis was always placed upon personal and reciprocal loyalty and duty, both among samurai and between samurai and lord. But the Tokugawa period, the code had evolved to incorporate both the aesthetic and ascetic elements that are contained in Zen discipline.”
Excerpted from: Murphy, Bruce, ed. Benet’s Reader’s Encyclopedia, Fourth Edition. New York: Harper Collins, 1996.