Ryo Hisanobu was the son of Ryokai, a Yamashiro smith of the late Kamakura period. He used the common name Kurozaemon no Jo, a detail confirmed by a critically important tachi bearing the full inscription "Ryo Hisanobu" together with the date Kagen 2 (1304). Among his dated works, examples from the Kagen, Tokuji, and Enkyo eras survive, placing his active career firmly in the closing decades of the Kamakura period. His workmanship stands close to that of his father, tending toward suguha-based constructions, and extant signed works are extremely few.

Hisanobu's blades characteristically display ko-itame mixed with conspicuous streaks of masame tendency, with fine ji-nie and a whitish shirake-like utsuri. The hamon is typically a suguha-cho mixing small gunome and slight midare or choji tendencies, with ko-ashi and adhering ko-nie; the nioiguchi at times shows places of urumi. His tachi tend toward long, dignified forms with deep koshizori, evident funbari, and ko-kissaki -- a configuration that conveys the stately bearing of the late Kamakura period. In the forging, the flowing itame with standing grain is a hallmark, and the overall dekiguchi clearly expresses the characteristic manner of the Ryokai group.

Hisanobu's significance extends beyond his own production. The emergence of his signed tachi bearing the name Kurozaemon proved that a Juyo Bunkazai-designated tachi previously attributed solely to Ryokai was in fact a collaborative work between father and son, fundamentally revising the understanding of both smiths. As one of the very few signed works by this maker, each surviving example possesses exceptionally high documentary value. His kodachi with ubu nakago and well-preserved inscription further reinforces the reference value of his oeuvre for the study of the Ryokai lineage.