Yuien 唯圓 (c. 1222–1289), Kantō Shinshū disciple of 親鸞 Shinran, head of the Kawada 河田 dōjō in Hitachi 常陸 province (modern Ibaraki), and traditionally identified as the author of the Tannishō KR6t0372. The identification rests on internal textual evidence (the author refers to himself as a direct hearer of Shinran’s teaching and as a Kantō resident) and on a marginal note in the Rennyo-shōnin shahon (Rennyo’s 1477 autograph copy of the Tannishō) which names him. Yuien appears in three of Shinran’s surviving letters from the Mattōshō KR6t0370 corpus, on each occasion as a recipient of doctrinal counsel. He visited Shinran in Kyoto in Kenchō 9 / 1257 (Shinran’s age 84) to consult on doctrinal questions, an episode recounted in Tannishō ch. 9. He died at the Kawada dōjō c. 1289. The identification is universally accepted in modern Shinshū scholarship though not absolute; no contemporary documentation under his own hand survives.