Kantei
A short, wide, almost straight blade, whole, with the short two-hole tang, on a black background.

Chikuzen and Nagato · Samonji school · Nanbokuchō

Yasuyoshi (安吉)

A swordsmith of the Samonji school of Chikuzen in the Nanbokuchō, who ended up in Nagato, with two meibutsu tantō: his period, his work, his famous works and his sources

Yasuyoshi (安吉, Yasuyoshi), who signed 左安吉 (Sa Yasuyoshi), was a swordsmith of the Samonji school of Chikuzen, present-day Fukuoka, in the Nanbokuchō. He is regarded as the son or pupil of Samonji and, by the mid-14th century, he was signing in Nagato. He is above all a swordsmith of large tantō, two of them meibutsu.

Tokyo National Museum, via ColBase

1357 and 1362
His two dated blades
2
Meibutsu tantō
4
Important Cultural Properties
On this page
  1. Quick profile
  2. In short

Quick profile

Name
Yasuyoshi, also Sa Yasuyoshi from the 左 (sa) signature of his school HD
Kanji and reading
安吉 (Yasuyoshi); signatures 左安吉 (Sa Yasuyoshi) and 長州住安吉 (Chōshū-jū Yasuyoshi) HD
Period
Nanbokuchō, 14th century; blades dated Shōhei 12 (1357) and Shōhei 17 (1362). The dates of his birth and death are not known HD
Province
Chikuzen (Fukuoka) and, later, Nagato (Chōshū), in present-day Yamaguchi HD
School
Samonji (左文字), or the Sa school, of Chikuzen HD
Master and lineage
Son or pupil of Samonji, according to the Tokyo National Museum and Kotobank AT
Documented fact and tradition
Documented: his signed blades, two of them dated, and the Nagato signature. Tradition: that he was Samonji’s son and that Samonji himself was called Yasuyoshi. AT

In short

What we know. That he signed large tantō as 左安吉 (Sa Yasuyoshi) or 安吉 (Yasuyoshi), one dated 1357 and another 1362, the latter already as a resident of Nagato, and that several are Important Cultural Properties.

How we know it. From those blades, described by the Tokyo National Museum, the Agency for Cultural Affairs and the NBTHK.

What we do not know. When he was born and died, and whether he was Samonji’s son or only his pupil.

Sections

  1. Samonji · Southern Court · Nagato Life and times Son or pupil of Samonji, his two dates and his move to Nagato.
  2. Large tantō · itame and nagare · ko-notare Work and style Sugata, jihada, hamon, bōshi, horimono and signature: the kantei keys, and where the sources disagree.
  3. Meibutsu · Important Cultural Properties Famous works The Hitotsuyanagi and the Heki Yasuyoshi, the Inuyama tantō and his other designated blades.
  4. Bibliography and credits Sources The sources consulted on 4 October 2026, with their links, and the credit for each image.