Inventing the ninja ancestor: Prince Shōtoku and the media circuits of martial tradition

This article traces the modern invention, transnational circulation, and persistence of the claim that Prince Shōtoku (574–622), the ancient Japanese regent, founded or patronized ninjutsu. While early chronicles portray Shōtoku as a statesman, Buddhist patron, and military leader, little to no premodern evidence connects him to such espionage traditions. Drawing on archival research, textual analysis, and media history, the article shows how this genealogy emerged in postwar Japan through Fujita Seiko (1899–1966), a self-styled ninja, and was expanded by the local historian Okuse Heishichirō (1911–1997) into a narrative linking Shōtoku with Sun Tzu and The Art of War. It then crossed the Pacific through English-language intermediaries to shape martial arts culture in the Western world, before ultimately resurfacing in a 1988 Japanese television series and a 1998 California courtroom. Rather than treating this genealogy as mere historical distortion, the article examines how its durability derives from the media circuits through which it has been reproduced: each iteration – martial manual, encyclopedia entry, television program, or courtroom testimony – reinforced the narrative’s authority without independent verification. The article concludes that martial genealogies are best understood not as fixed historical records but as flexible resources whose authority derives from circulation rather than origin.