Tametsugu is traditionally said to have been the son of Go Yoshihiro and to have studied under Norishige; however, the consistently observes that "from the standpoint of chronology, there remains room for further examination." preserve works signed " no Fujiwara Tametsugu" dated Enbun 2 (1357) and 2 (1369), while an extant blade signed "Noshu ju Fujiwara Tametsugu" bears the date 7 (1374). From these facts it is understood that "between 2 and 7 he moved from to ," placing his working life firmly in the period across two provinces within the broader northern tradition.
In workmanship, Tametsugu "shows a forging in which appears with conspicuous standing grain," mixed with and , with "thickly formed " and frequent . The steel characteristically displays "a somewhat blackish tone" -- a surface quality the identifies as Hokkoku-, "the characteristic texture particular to works from Japan's northern regions." His tempering encompasses several modes: with as the principal tone; with mixed ; and -based patterns into which is intermingled. In all these modes, " appears along the , adheres well," and and run vigorously. The "tends to be somewhat " -- a subdued quality that, combined with the dark forging, sets his work apart from the brighter - masters he echoes. Stronger examples introduce , , and , and his frequently terminates in vigorous , at times "becoming flame-like."
The recognizes that Tametsugu's work "at first glance can recall the work of upper-ranked masters," yet consistently distinguishes it through the standing , the dark kana-iro tone, the -tending , and the "whitish, kasu-dachi-like appearance" termed Hokkoku-mono. Across his designated blades, the evaluative refrain is that "the characteristic features and merits of Tametsugu are fully manifested in both and ." Several note the condition of his works as -- "sound and well-preserved" -- and emphasize the "forceful spirit" and "martial vigor" that pervade his output. One blade bears a cut-in inscription recording its use at the Summer Campaign of Osaka, attesting to the esteem in which these swords were held as practical weapons centuries after their making.