In the oldest treatises
- The 観智院本銘尽 (Kanchi-in-bon Meizukushi), the oldest sword treatise, from the late Kamakura, contains two trees. In the first, the lineage of the swordsmiths of Sagami, Kunimitsu is a pupil of Sukezane, of the Ichimonji school, and from him descend Kunishige, Kunihiro, Yukimitsu and Masamune. In the second, that of the swordsmiths of Kamakura, he appears as 行光藤三郎入道 (Yukimitsu Tōsaburō nyūdō), a pupil of Kunimitsu.
- For the NBTHK, according to many old books, Tōsaburō Yukimitsu was a pupil of Shintōgo Kunimitsu, somewhat older than Masamune and a swordsmith of an earlier generation.
- The Japanese Wikipedia’s list of swordsmiths places him in Sagami, in the school of 新藤五 (Shintōgo), with Kunimitsu, Sukezane, Masamune and Sadamune.
The father of Masamune?
- The Tokyo National Museum gives him as the son or pupil of Shintōgo Kunimitsu and as the father or adoptive father of Masamune.
- The Japanese Wikipedia records three versions: the manuscript 竹屋理安本 (Takeya Rian-bon), of 1579, makes Masamune the son of Yukimitsu; another, his younger brother and later his adopted son; and another, the son of Kunimitsu.
- The story of the 八木節 (Yagi-bushi) about Masamune’s reunion with his father Yukimitsu is, for the Japanese Wikipedia, a later invention.
The dates
- The NBTHK gives the dated works of Shintōgo Kunimitsu, his master according to the genealogies: from Einin 1 and 6 (1293 and 1298), Enkyō 2 (1309), Shōwa 4 (1315), Gen'ō 2 (1320) and Genkō 2 (1322), and the Japanese Wikipedia extends his dated blades to Genkō 4 (1324). According to the NBTHK, Kunimitsu trained three great swordsmiths: Yukimitsu, Masamune and Norishige.
- No dated blade by Yukimitsu is known in the sources consulted: his period is inferred from that of his master.