Nobufusa was an early smith of the Fukuoka group in Province, counted among the swordsmiths who served as — "on-duty smiths" — for Retired Emperor Gotoba. Sword reference works place his period of activity around the Kenpo era (1213–1219). There has been a theory identifying the smith signing with the character 延 as the person as the Nobufusa written 信房; however, the prevailing scholarly view holds that they were different individuals. Extant works that are securely authenticated and signed are exceedingly few; apart from the at Hie Shrine (Important Cultural Property), the in the Tokyo National Museum (former Imperial collection), and the in the Hayashibara Museum of Art (Important Art Object), only a very small number are known.
Nobufusa's forging is characteristically , at times mixed with and tending toward a dense, packed texture the terms . The carries and prominent — most often , with also observed — and the presence of further enlivens the surface. The is fundamentally , a straight-temper foundation mixed with , , and ; and enter plentifully, and adheres well, producing what the describes as abundant internal activity within the temper. Certain works display a at the base and proceed into a broader . The is typically straight, returning in . His present the classic early silhouette — slender, with high , evident , and — yielding what the consistently characterizes as an elegant overall form.
The repeatedly observes that the and of Nobufusa's work "clearly present the archaic aesthetic virtues characteristic of early work," combining an antique grace with a refined, high-class style. His signed blades, being scarce, are prized not only for their artistic merit but also as precious reference material. Several bear connections to distinguished provenance, including the Kujo family and the Izumo Senke family, and are accompanied by historical appraisals such as by Kochu. Taken together, his oeuvre demonstrates the high level of forging technique that defined the earliest generation of the Fukuoka school and its foundational role within the tradition.