Ryokai (了戒) was a swordsmith of the Rai school active in Yamashiro Province during the late Kamakura period. One tradition holds that he was a son of Rai Kunitoshi; however, extant works bearing dated inscriptions include the eras Shoo, Einin, Kagen, and Enkyo, placing him in virtually the same time frame as Rai Kunitoshi. If one assumes that the "two-character Kunitoshi" (niji Kunitoshi) and "Rai Kunitoshi" refer to the same individual, there is no chronological difficulty; but if the two are regarded as different persons, then Ryokai should more properly be considered the son of the two-character Kunitoshi. An alternative scholarly view regards him not as a son or pupil but rather as a fellow disciple contemporary with Rai Kunitoshi. A joint work (gassaku) with his son Ryo Hisanobu, dated Kagen 3 (1305), survives alongside the Important Cultural Property tachi at Atsuta Jingu and the naginata in the Tokugawa Art Museum inscribed by Hisanobu, together clarifying the relationship between the two smiths and the period of their activity.

Ryokai's workmanship is extremely close in style to that of Rai Kunitoshi, yet several distinguishing features are consistently observed. The jigane tends to incorporate a masame inclination and takes on a somewhat whitish cast, frequently displaying shirake-utsuri or a faint nie-utsuri-like effect. The hamon is characteristically a calm chu-suguha, at times mixed with ko-choji, ko-gunome, or a shallow notare tendency, rendered in ko-nie-deki with well-formed ashi and yo. A hallmark trait is that the nioiguchi of the suguha temper shows an urumi tendency — a moist, soft quality — particularly around the koshimoto. Compared with Rai Kunitoshi, the nioiguchi is one level tighter and the interior of the temper tends to appear comparatively quiet, such that the ji and ha can feel somewhat restrained in strength. Fine kinsuji, sunagashi, and occasional yubashiri provide subtle internal activity, while the boshi typically runs straight or in gentle notare, turning back in ko-maru. Kyoto-style saka-ashi and gyaku-ashi appear in certain works, reinforcing the blade's identity as Kyo-mono.

Ryokai occupies a position of considerable importance within the Rai school as a smith whose refined and subdued manner represents one of the most elegant expressions of the Yamashiro tradition. His tachi characteristically display slender, graceful forms with pronounced taper, deep wazori curvature, funbari, and ko-kissaki — an orthodox late-Kamakura silhouette of quiet dignity. Several signed and ubu examples survive, and the existence of the dated gassaku with Hisanobu constitutes an exceptionally valuable reference for establishing the lineage and chronology of the Rai school. Hon'ami appraisals, including origami by Kochu and kinzogan-mei attributed by Koson, attest to the esteem in which his work has long been held. One blade carries a tradition of having been worn by Miyamoto Musashi. At his finest, Ryokai's work bears a striking resemblance to Rai Kunitoshi and possesses a calm, archaic elegance that is deeply appealing.