The history of bushido runs in the opposite direction from its legend. The legend has an ancient, unified warrior code, handed down from the medieval samurai and finally revealed to the world in modern times. The documentary record shows something closer to the reverse. The word bushido is rare in premodern writing; Edo-period warrior ethics were plural and contested, ranging from Confucian administrative moralism, since the samurai of that long peace were bureaucrats far more than fighters, to the extreme death-devotion of the Hagakure, itself a marginal text in its own day, dictated by a retainer who had never fought a battle. No single code was taught, and the behavior of actual warriors matched the ideals about as well as European chivalry matched knightly practice. The systematic bushido the world knows was assembled in the Meiji era, after the samurai class itself had been abolished.
Oleg Benesch's study traces the construction in detail: nationalist writers of the 1880s and 1890s, anxious to match Western gentlemanship and chivalry with a native equivalent, gathered selected strands of the warrior past into a coherent ethic, which was then propagated through the schools and the army, retrojected onto history, and conscripted into imperial ideology through 1945. None of this makes bushido fake; invented traditions are real traditions with short pedigrees. It makes it modern, and the honest article states the direction of assembly: the code did not produce the nation's ideal, the nation's ideal produced the code.