The versions of his origin
The most repeated: he was the son of Rai Kunitoshi, born when his father was seventeen; he took holy orders at sixteen under the name Ryōkai and later returned to the forge. Some versions say that he also learned with Ayanokōji Sadatoshi. Others, recorded by Sesko: he was a swordsmith from Nara who went to Kyoto to study with Kunitoshi; or he became a monk when already older; or, for those who distinguish two Kunitoshi, the Niji Kunitoshi (二字国俊, Niji Kunitoshi) and Rai Kunitoshi, he was the son of the first and brother of the second. The Tokyo National Museum says that he is held to be a swordsmith of the Rai school who lived in Sakamoto, in Yamashiro, and the son or student of Rai Kunitoshi according to one version.
Dates
Sesko calculates: if he was born when Kunitoshi, born in 1240, was seventeen, he would be from the Kōgen era (康元, Kōgen), 1256; the 『古刀銘尽大全』 (Kotō Meizukushi Taizen) gives the same year. His first dated blade is from the Shōō era (正応, Shōō), of 1290, when he would have been 34; blades from the Einin (1293–1299) and Kagen (1303–1306) eras follow, and the last is from the Enkyō era (延慶, Enkyō), of 1309.
His death
The Taizen says that he died in the fourth year of the Shōkyō era, aged 72; but the Shōkyō era (正慶, Shōkyō) lasted only two years, from 1332 to 1334. If he died at 72, it would have been in the Karyaku era (嘉暦, Karyaku), around 1328. Sesko believes that he died before his father, because his dates end long before those of Kunitoshi, which reach 1321.
In a list of 1313
In 1313 the bakufu asked for a report on the cutting swords of the country, the 注進物 (Chūshin-mono), with sixty swordsmiths. Ryōkai appears in it and his father does not. Sesko reads this as a sign of which swords were considered appropriate for high society, not of their real sharpness.
Lineage
From the Ryōkai branch come Hisanobu, who signs as Ryōkai’s son, and the first Nobukuni, of Kyoto. The Heibonsha encyclopaedia adds that his descendants moved to Tsukushi (筑紫, Tsukushi), in Kyūshū, and founded local workshops there. Sesko treats the Ryōkai and Nobukuni branch as a school separate from the Rai. The Japanese Wikipedia only names him in passing, among the swordsmiths of the Rai school.