On a long-signed dated Kagen 2 (1304) the smith cut his full name and personal title, Kuro-zaemon-no-jo Hisanobu, and that single inscription fixes much of what is known of him. Ryo Hisanobu, signing Ryo-Hisanobu, was the son of the founder of the Ryokai school of Yamashiro and the second generation of that line, working at the very end of the period on the dated evidence of his surviving blades, the year-signatures Kagen, Tokuji and Engyo placing him almost level with his father at the turn of the fourteenth century. The Ryokai school stood among the recognized offshoots of the great workshop of Kyoto, and the published sources describe Hisanobu as carrying his father's hand on with little change. He is rated Jo-jo in the reference texts, a high standing for so little-recorded a smith, and his work survives in a handful of designated blades, signed and attributed, by which his manner can be read.
His is the quiet Yamashiro of the Ryokai line. Over a forging of or that flows toward and stands a little open, the carries dust-fine and the school's whitish , which on the slenderer blades rises in a straight band from the before spreading up the . The temper is a calm chu- or , or a mixing small with a few and , the tightening and clouding into in places, with and entering, a faint fraying of along the and fine , the closing straight into a small . The first the published sources call an offering that well displays the characteristics of the Ryokai school, the phrase 「了戒一派の特色がよく表示された出来口」 standing as a fair summary of his hand.
The is the foundation of the recognition. Across every one of his blades the whitish stands in the , the inherited Ryokai tell that separates the line from the parent, in whose work it is essentially absent. The leans toward , the Yamato-ward drift of this offshoot, so that the surface stands and flows where the packed stays smooth, clinging dust-fine and an occasional running. In the the calm shows minute work, and entering thickly on the best pieces, the clouding softly, an occasional or drifting across, a little showing low on one . On his finest attributed the published sources praise the abundant and , the good and the finely worked together, judging it a particularly fine example among his attributed work with the words 「同工極め中にあって特に優品といえる」.
The small body of his designated work divides into two registers. The first is his rare signed survivals, and carrying a three-character Ryo-Hisanobu toward the above the , and the one long-signed dated giving the full personal name; one is carved with and on the and and on the , the late- Kyoto manner. The published sources call the signed precious as one of the few in- works of this smith, and well preserved, its hand recalling the father, 「作風は父了戒を想わせるような出来口」. The second register is blades attributed to him on the reading, one an of well-made , one an slightly high in the . Signed work is described again and again as extremely few, which is why his year-signed and dated pieces carry such documentary weight, one of them called of very high reference value as one of the scarce in- works of this smith, 「数少ない同工の有銘の作として資料価値は頗る高い」.
The is drawn against two near neighbours. The first is Kunitoshi, the parent of the line, against whom the published sources resolve one of his directly: the , and other changes at the -border of his fine read a degree quieter and lonelier than Kunitoshi, the calm narrow line still showing minute activity, the verdict 「来国俊に比してやや蕭然たるもの」, with the running straight into a settled , so that the Hisanobu attribution is correctly affirmed. The and more marked, the tighter and the whole calmer, these are the points that part him from . The second neighbour is the father himself, from whom Hisanobu is separated less by any feature than by the signature, since signed work of the son is rarer still; a plain Hisanobu is at a glance easily taken for the father's, and a soft Kunitoshi for either of them. His single most consequential blade is the dated that, by giving his personal name, established his zokumyo as Kuro-zaemon and through it showed that an earlier nationally designated , once read as the father's sole work, is in fact a joint work of father Ryokai and son Hisanobu.
Hisanobu has no National Treasures and no Important Cultural Properties of his own, and none of his recorded blades is locked permanently out of private hands; his standing is that of a scarce but genuinely collectable name. Five of his blades are on the official designation record, all at the tier, and the published sources lean on his year-dated work and on outside documents to fix his place, the Tokuji 3 in the Tokugawa Art Museum carrying the inscription 「了戒子息久信作」 that confirms him as Ryokai's son. No provenance owners are recorded for his designated blades, whose whereabouts of record run to private collections across several prefectures. A signed Hisanobu, and with its intact, is among the scarcer things a collector of late- Yamashiro work could hope to encounter, coming to light only from time to time and prized as documentary evidence as much as for itself; a or attributed to him appears a little more readily, and it is on these, with their and clouding read against the quieter line, that his hand is most often met. The published sources close on one such blade as a calm fine that yet shows minute work, 「静閑な細直刃ながらも微細な働きをみせる」, a deep and savoured offering, which is as fair a verdict on the smith as on the blade.