Naotsugu is one of the skilled and representative smiths of the school of Province, active from the late period into the early period. Sword-signature reference works place his activity as beginning around the Karyaku era, and extant dated works range from Gentoku (1329) through Jowa, Shokyo, Kenmu, and Kanno, spanning roughly the 1320s to the 1350s. Among pieces bearing the Gentoku and Kenmu dates, several carry the court titles Saemon-no-jo and Sahyoe-no-jo. Together with smiths such as Yoshitsugu, Naotsugu is counted among the foremost craftsmen of the tradition during its later flowering. The reference works further distinguish a first and second generation: the first dated from Shoo through Kenmu, and the second from Ryakuo through Enbun, with Jowa-dated pieces likewise assigned to the second generation. The lineage itself traces its high reputation to the early eleventh-century Sarugakki, which cites "the swords of " among the noted products of the provinces; thereafter, smiths of this lineage emerged and flourished chiefly in the lower basin of the Takahashi River, their works broadly divided into for pieces through the mid- period and for those extending through the era.
Naotsugu's works are fundamentally grounded in , yet display a range of expression across the body of designated pieces. The characteristic forging is a tightly packed mixed with , in which fine adheres thickly, delicate are interwoven, and — whether faint, , or — stands with clarity. A mottled, patch-like texture frequently appears in the ground. The ranges from narrow to medium with extremely shallow , incorporating , , , and . The is characteristically tight and bright, described repeatedly as — bright and clear. In certain works, adheres well, with and fine appearing, while uchi-noke and enliven the . The typically runs straight, turning back in with a tendency toward a pointed tip and occasional faint . Notably, while the prevailing style of -period is generally , several of Naotsugu's pieces are distinguished by their well-adhering — a point that approaches the manner of -period work of the school. In at least one designated , a florid - temper departs from the foundation, demonstrating the breadth of his repertoire. The so-called — a crepe-like surface texture — appears among his signed , and is a recurring feature in works of bold, imposing form.
Across the designated corpus, the repeatedly characterizes Naotsugu's output as works in which "the characteristic features of the late- school are clearly expressed" and in which "both and are " — sound and well-preserved. The tightly forged texture with its finely woven and distinctly visible draws particular commendation. Multiple praise the as tight and keenly clear, and note the ample — well-preserved flesh — that lends his a firmly built, weighty impression. His dated inscriptions, bearing official titles and era names in fine chisel work, are valued as precious documentary material for the study of the school. Within the broader tradition, Naotsugu occupies a pivotal position at the transition from the manner of the period to the tighter, brighter workmanship of the era, and the regards his finest pieces as outstanding works that fully demonstrate the high level of technique attained by the school in this period.