Role of the Sword Futsunomitama-no-tsurugi in the Origin of the Japanese Bushidō Tradition

One of the formative narratives in Japanese martial arts is the bestowal of the mystical sword “Futsunomitama-no-tsurugi” upon Emperor Jinmu, the legendary founder of Japan. Within the Kashima Shinden Bujutsu lineage, this bestowal is attested as a critical event in the initiation of the principles of Bushidō martiality. However, the practical reasons for its significance has been unclear. Drawing on historical and archaeological records, in this paper we hypothesise that the physical conformation of the legendary sword Futsunomitama-no-tsurugi represented a comparatively incremental progression from the one-handed short swords imported from mainland Asia. These modifications, however, allowed for a new, two-handed style of swordsmanship, and therefore it was the combination of the physical conformation of Futsunomitama-no-tsurugi and the development of appropriate techniques for wielding it that formed the basis of the martial significance of the “Law of Futsu-no-mitama”. Drawing on various traditions and records linking Futsunomitama-no-tsurugi to the Kashima Grand Shrine, we also argue that this new tradition of swordsmanship was the nucleus around which the Kashima Shinden Bujutsu lineage would develop, and therefore represented a critical first step towards the later concepts of Bushidō. Based on the kabala of the Kashima Shinryū, we also present a working model of what the techniques for usage of Futsunomitama-no-tsurugi might have been, and provide an account of an experiment testing its application