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

　It is said that Sa Yasuyoshi was the son of Samonji, a swordsmith in Chikuzen no Kuni, whose signature was "Sa." Since Yasuyoshi's swords forged in the 12th and 17th years of the Shohei era (1357 and 1362) now exist and Shohei is the name of an era used by the Southern Court, it is believed that he used to live in an area ruled by the Southern Court. While Samonji is said to be a disciple of Masamune in Sagami no Kuni due to his aggressive nie (martensite crystals) style, Yasuyoshi's style features kogunomeba with konie (small martensite crystals). The name derives from the fact that the Kyoho Meibutsu Cho (a book of quality products in the Kyoho era) states that it was owned by Hitotsuyanagi Naomori, a warlord of Mino no Kuni. It was later owned by the Maeda family.