Bushido: The Soul of Japan, published in English in Philadelphia in 1900, is one of the most consequential works of religious and ethical explanation ever aimed across a cultural boundary, and one of the least reliable. Its author, Inazo Nitobe, was an agricultural economist and Quaker convert married to an American, writing to answer a question put to him abroad: how does Japan teach morality without religious instruction in its schools? His answer organized the samurai inheritance into a tidy octave of virtues, rectitude, courage, benevolence, politeness, sincerity, honor, loyalty and self-control, and presented it as Japan's equivalent of chivalry, gracefully cross-referenced to European philosophy and the Bible for an audience that knew those and not Japan.
The book was a phenomenon; Theodore Roosevelt distributed copies, and for decades it fixed the Western image of Japanese ethics. Specialists have been correcting it ever since. Nitobe knew the Western canon far better than the Japanese martial literature he claimed to summarize; his bushido is a Meiji Christian humanist's idealization, and scholars note that the term itself was so uncommon that Nitobe could believe he had coined it. The religious framing of the book deserves its own caution: bushido is presented there almost as a faith, and the presentation fed later claims of an essential Japanese spirit that wartime ideology put to dark use. Read today, the book documents not the soul of the samurai but the soul of its moment, a bridge-builder's portrait of a tradition redrawn to be admirable to its audience.