Ko-Hōki Arietsuna

Ko-Hōki Arietsuna was a swordsmith who flourished from the late Heian through early Kamakura period in Hōki Province (present-day Tottori Prefecture), and was one of the important swordsmiths of the Ko-Hōki tradition, which inherited the lineage of Hōki Yasutsuna, renowned as the founder of Japanese sword-making. The Ko-Hōki tradition, with Yasutsuna as its patriarch, formed a lineage through Sanemori, Arietsuna, and Sadatsuna, representing a group of swordsmiths who undertook the earliest stages of Japanese sword-making rooted in the unique iron-smelting tradition of the San'in region.

Arietsuna's work inherits the technical lineage of the Ko-Hōki tradition while embodying the stylistic evolution during the transition from late Heian to early Kamakura. The jigane exhibits prominent ōitame and nagare itame patterns with thick jinie, displaying the characteristic 'Hōki-hada' distinctive to the Hōki tradition. This characteristic iron finish is the product of ancient smelting techniques using abundant satetsu from the Chūgoku Mountains, possessing a distinctly archaic beauty that clearly differentiates it from blades produced in other regions. The hamon primarily features a gentle suguha with admixtures of kochōji and komidaré; the ha-buchi displays large, active nie particles, with prominent kinsuji and sunagashi working powerfully throughout. The Ko-Hōki tradition's distinctive expression of vigorous, coarse nie vividly reflects the transitional aesthetic of the late Heian through early Kamakura period.

The tachi's proportions exhibit an intermediate form showing the transition from late Heian to early Kamakura. The transitional proportions evident in Arietsuna's work—shifting from the grand, expansive Heian tachi style of his predecessors Yasutsuna and Sanemori toward the robust, martial aesthetic favored in the Kamakura period—clearly demonstrate the temporal character of his blades.

Signed works by Arietsuna are extremely rare, with very few confirmed existing examples. However, as an important swordsmith in the Ko-Hōki lineage ranking second only to Yasutsuna and Sanemori, the small number of surviving examples possess high cultural heritage value as documents conveying the earliest phases of Japanese sword history. Known surviving examples have been designated as Important Cultural Properties and reside in museum and private collections.