The Ezo tradition designates a collective body of sword-fitting metalworkers active from the period through the early period, producing a distinctive class of mountings commonly known as Ezo-kanamono. The name itself is something of a convention: as the has noted, these fittings "are of course not products of Ezo itself, but rather were made in Japan for the Ainu and circulated through trade — for example, exchanged for bear skins." The precise region of manufacture remains uncertain, and the acknowledges that "it is not possible to determine clearly in what region a work of this kind was produced." What unifies the group is not a documented lineage of masters but a recognizable material vocabulary and a shared archaic character that the designation sessions have identified with remarkable consistency across nearly four decades of appraisal.
The technical hallmarks of Ezo work center on the use of or as the ground metal, "ranging from those with a whitish cast to those tending toward black," over which gilding is applied to the entire surface. The carving is executed in yobori — rounded, sculptural relief — frequently combined with pierced openwork () that is "finished with a notably clean, crisp appearance." Construction employs the archaic in'-ne paired-post system, contributing what the terms "an elegant antique quality." Scale is a defining feature: Ezo are consistently described as large or exceptionally large, with "a bold, imposing presence" suited to and other full-length mountings. In the finest examples, vigorous chisel handling produces figures of considerable force — paired lions, baku, peonies — rendered "in a bold and powerful manner" through confident, incisive cuts. Fine line engraving () is sometimes present, with cuts that "are crisp and stand proud." Gilding techniques include -, usukin-dashi, and keshi-watakin, and the works are occasionally finished with accents.
The most distinctive quality of Ezo-kanamono, and the one the returns to in virtually every appraisal, is the transformation wrought by age upon the gilded surface. As the gold wears through use and time, it enters the condition called suri-hagashi — a state of rubbed and abraded wear in which the dark ground metal emerges through the thinning gilt. This process yields what the sessions repeatedly characterize as "an abundance of antique color" and "a distinctive flavor rich in aged patina." The interplay between the worn gilding and the darkened base produces a depth of feeling the describes as "classically elegant" and "uniquely Ezo-like." Earlier pieces from the period display what is termed "the imposing old dignity characteristic of the period," while works appraised to the period are praised as "archaic and rich in taste, sufficiently conveying the feeling of its age while remaining refined." Across the corpus, the evaluative language is strikingly uniform: these are fittings whose value lies not in virtuosic innovation but in an austere, time-deepened beauty — works whose "emotive character, refined through the passage of time, has been transmuted into an antique fragrance."