Hiromasa was a swordsmith of ( Province), a name borne by several generations active continuously from the period through to the end of the period. Dated examples are rare, making it difficult to distinguish the individual generations with clarity; however, surviving dated works include blades inscribed Bun'an 5 (1448), Hotoku 2 (1450), Kosho 2 (1456), and Bunmei 3 (1471), placing the documented activity firmly within the mid to late period. A separate Hiromasa of the lineage in Province, traditionally regarded as a son of Yukihiro, is also known from the mid period around the Shohei era, and one blade attributed to this Hiromasa bears a gold-inlaid attribution reading "Ranoke."
The of Hiromasa's -line works is characteristically an tending toward standing grain, with and . The takes the form of , frequently mixed with that develops into (full-temper); , , , and appear, and the tends toward tightness. The typically enters in , sometimes becoming on the , and returns with a pointed tendency. A notable hallmark of this smith's output is the : virtually every signed blade bears elaborate carvings -- , grass-style , , -sho, hatahoko, and renben, often executed in raised relief () within grooves. These carvings are consistently described as "skillfully executed" and "splendid," and they constitute a defining feature of -made blades of this era. The -lineage Hiromasa, by contrast, displays a -based upon which adheres well with a bright, clear -- features that "strongly manifest the characteristics of the tradition."
Works by both lineages receive consistent praise. Of the Hiromasa, the observes that his blades display "both the period character of workmanship and the traditional manner of the ," and individual pieces are assessed as "one representative masterpiece among works of this era." Of the Hiromasa, the forging with accompanied by and a bright, clear leads to the assessment that the blade is "an especially fine example" among works attributed to this smith. Across both traditions, the name Hiromasa represents a sustained lineage of skilled craftsmanship that preserved regional forging idioms through several generations.