National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

Toshiro Yoshimitsu was a swordsmith of the Awataguchi school in Yamashiro no Kuni and is said to be a disciple of Norikuni or of Kuniyoshi. He was a renowned swordsmith of short swords and regarded as one of the three greatest swordsmiths together with Soshu Masamune and Go no Yoshihiro. Many of his short swords are listed in the Kyoho Meibutsu-cho (a book of quality products in the Kyoho era). This short sword is listed in the Kyoho Meibutsu-cho as "Iwakiri Natsuka Toshiro." Although the origin of "Iwakiri" is unknown, Natsuka Masaie received this short sword from Toyotomi Hideyoshi. Its ownership later shifted to Fukushima Masanori and then to the Okudaira family. This is a relatively small sword among Yoshimitsu's short swords and the jigane (ground metal) has a small wood grain pattern (koitame) while the hamon (blade pattern) is in the suguha (straight) style with konie (small martensite crystals), which clearly demonstrates the characteristics of Yoshimitsu. The short sword accompanies a certificate of authenticity written in 1648 by the 11th Koon of the Honnami family.