Sōshū Sadamune

Sōshū Sadamune was a swordsmith who worked in Sagami Province, Kamakura, from the late Kamakura period through the period of the Northern and Southern Courts. His common name was Hikoshiro. He is said to be either the son or adopted son of Masamune, the master craftsman who perfected the Sōshū school, though no definitive proof has been obtained; however, he is regarded as the legitimate successor to Masamune's workshop. In the "Shin Satsu Ōrai," compiled during the Northern and Southern Courts period, it is recorded: "Gorō Nyūdō and his son Hikoshiro, both master craftsmen of an era," and he was recognized early on as an eminent master of his time.

His work style strongly inherited from his master Masamune. The jigane exhibits tightly worked ko-itame jihada with good jigashio, and jikei appear frequently. The hamon is composed principally of notare with interspersed gunome, and the blade displays vigorous activity of kinsuji and sunagashi within the hamon, with a deep nioi-guchi displaying bright, sharp nie. However, compared to Masamune, the jikei and kinsuji are less pronounced overall; Sadamune's individuality lies in his more restrained and refined finish. He also excelled at blade carving, and examples with carved designs such as Sanskrit letters and lotus pedestals are known.

Sadamune has almost no authenticated extant works with signatures in place, and most of the transmitted works are unsigned works authenticated by the Honʼami family. The red signatures carved on the tangs are not from the craftsman himself but are authentication signatures of the Honʼami family, and they have been transmitted as works of Sadamune through their authentication and certificates.

Representative works survive in large numbers as National Treasures and Important Cultural Properties. Among National Treasures are the "Kikkō Sadamune" (tachi, Tokyo National Museum), named after the hanamari kikkou pattern hair-carved on the tang reverse; the "Tokuzen'in Sadamune" (tantō, Mitsui Memorial Museum); the "Fushimi Sadamune" (tantō, Kurokawa Institute of Classical Japanese Arts); and the "Terasawa Sadamune" (tantō, Agency for Cultural Affairs). Among Important Cultural Properties, the "Monoyoshi Sadamune" (wakizashi, Tokugawa Art Museum) is well known; according to a tradition, Tokugawa Ieyasu highly valued this blade, and whenever he drew it, he was certain to emerge victorious. It later passed to the Owari Tokugawa family.

In terms of lineage, the succession from Masamune to Sadamune is positioned as the legitimate line of the Sōshū school. On the other hand, in the compilation of the Masamune no Jittetsu done in later centuries, it is generally held that Sadamune, as an adopted son (treated as a biological heir), is an exception and not counted among them, and he has been treated as a special case—not as a disciple but as the successor to the main Sōshū house. In the Kyōhō Meibutsuchō, compiled by the Honʼami family at the command of the eighth shogun Tokugawa Yoshimune, Sadamune's works number some twenty items, of which four are designated National Treasures, twelve are Important Cultural Properties, and three are Important Art Objects. As the legitimate successor to Masamune, Sadamune is evaluated as a representative smith of the Sōshū school.