By Rai Kunimitsu
Kamakura period/Karyaku 2(1327)
Tokyo National Museum
The Rai lineage of swordsmiths from Kyoto was founded by Rai Kuniyuki and continued by Kunitoshi and the latter's son Kunimitsu. Kunimitsu, the creator of this blade, was active from the late Kamakura period (1185-1333) to the Nanbokuchô period (1333-1392) and became the principle swordsmith of the lineage. His works include both blades with straight tempering patterns and those with curving irregular ones. A large number of his tachi and short swords (J. tantô) survive.
With its particularly strong curvature showcasing the straight tempering pattern that is emblematic of the Rai lineage, this blade is one of Kunimitsu's most famous works. His signature and the date are inscribed in a single line.
In 1899 (Meiji 32), Tokugawa Iesato (1863-1940) presented this sword to the crown prince who would later become Emperor Taishô (1879-1926, r. 1912-1926).