Aoe Sadatsugu

Aoe Sadatsugu was a swordsmith active around the Jōgen era (1207–1211) of the early Kamakura period in Aoe (present-day area around Mabi-chō, Kurashiki City), Bitchū Province (present-day western Okayama Prefecture). He is known as one of the representative master smiths of the Aoe school. He was a son of Moritsugu and is said to have served as a bankaji (court smith on monthly rotation) for the retired emperor Go-Toba. The Aoe school is a group of smiths in Bitchū Province, including Moritsugu, Tsunetsugu, Tsugunao, and Sadatsugu, who formed a lineage and represent Bitchū Aoe in the history of Japanese swords of the Kamakura period. Note that the gokaden refers to Yamashiro, Yamato, Bizen, Sōshū, and Mino, and the Bitchū (Aoe) tradition, which is not included among them, is known for its distinctive style.

Sadatsugu's blades clearly show the style of Ko-Aoe. They embody, with a high degree of refinement, the sumi-hada, the most distinctive feature of the Aoe school: a distinctive surface in which jifu, patches that appear dark and changed in color, emerge within a jigane that is clear and blue. This sumi-hada is a beauty unique to the Aoe school and is regarded as one of the most important indicators for identifying Aoe works in sword appraisal. The jigane has a varied texture, mainly itame mixed with masame, with fine, even ji-nie, and chikei and utsuri standing out, presenting a rich visual impression.

The hamon shows a composition that is serene and dignified, consisting of a gentle suguha and ko-midare, which are typical of the Aoe school, mixed with ko-chōji and ko-gunome. The habuchi is accompanied by fine, uniform nie, and within the hanaka, long sunagashi and fine kinsuji appear. Overall, it displays the essence of the beauty of the Aoe school's hamon, possessing a calm and refined dignity.

The tachi of Ko-Aoe are characterized by a taihai in which they have koshi-zori, a pronounced curve at the koshimoto. Toward the tip, the curve becomes shallow and the mihaba narrows, forming a ko-kissaki. Inscriptions are confirmed as the two-character signature "Sadatsugu," and both signed works (zaimei-saku) and unsigned works (mumei) with a transmitted attribution survive. At present, the tachi inscribed Sadatsugu (privately owned) is designated a National Treasure, and the tachi inscribed Sadatsugu held by the Tokyo National Museum, together with the famous Ō-Aoe and Ko-Aoe (meibutsu) (both with kinzōgan-mei, privately owned), are designated Important Cultural Properties.