Nihonto Club

Period: starts Shoō (1288-1293)
Nagasa: 65.1cm (shortened)
Sori: 1.2cm
Tsukurikomi: Kanmuri-otoshi-zukuri
Mei: mumei
Sayagaki: Honami Koson
Paper: Tokunō Kazuo (得能 一男) (Den Masamune / 1329)

Gorō Nyūdō Masamune (Kamakura): As is well known, following the attacks by the Chinese fleets and the alarming failure of tachi swords to penetrate Chinese body armor toward the end of the Kamakura period, various swordsmiths were summoned to Sagami to produce more robust swords. In doing so, Masamune and the other smiths sought to improve forging techniques and blade construction. It was in this context that the Soshu tradition was established.
Sword History: According to the sayagaki and accounts by Tokunō Kazuo (author of Tōkō Taikan), the sword was presented by Shogun Tsunayoshi (徳川綱吉) to Yanagisawa Yoshiyasu (柳沢吉保). My translation of the text in the origami reads: "The sword was handed down through the Yanagisawa family of the Yamato-Koriyama Domain; Shogun Tsunayoshi presented it to Yanagisawa Yoshiyasu in recognition of his services as the magistrate in charge of the construction of the Honchūdō Hall at Kan'ei-ji Temple." The sayagaki dates this donation to the second day of the eighth month of the eleventh year of Genroku (1698).
Kanmuri-otoshi-zukuri: The construction of this sword derives from the common practice of repurposing naginata into swords. Masamune was one of the first smiths to incorporate the robust shaping of the naginata directly into the initial forging of swords in order to create stronger blades. His son, Sadamune, perfected this sword style.