Sakon Shogen Tsunetsugu was a swordsmith of Province active in the late period, whose period of production is established by an extant work dated Genko 2 (1322). His precise lineage has not been clarified, though it has been suggested he may represent a continuation of the line of Masatsune. He is to be distinguished from the contemporaneous Tsunetsugu, a smith of the neighboring province who signed with the title Saemon no Jo --- a distinction that, as the has noted, was only firmly established in modern times. Indeed, even an by Kodon dated 2 (1662) identified a Tsunetsugu blade as " Tsunetsugu," demonstrating the long-standing influence of appraisal upon the sword world and the historical conflation of these two smiths. Extant signed works by Sakon Shogen Tsunetsugu are few, rendering each surviving example of particular documentary importance.
Within Tsunetsugu's oeuvre, the identifies two principal modes: works fundamentally based on , and those in which and are more conspicuous. What is common to both is that the interior of the is richly suffused with , and fine frequently appear. His is typically mixed with , forged tightly, with fine adhering densely and entering, while --- and in some pieces near the edge transitioning to toward the --- stands out prominently. The , rendered in , characteristically shows and entering well, with appearing alongside the . The tends toward , turning back round, or finishing in . Because Tsunetsugu particularly excelled at , his work is, as the cautions, "liable to be misappraised as that of the group," and his blades show areas of close resemblance to work of the period.
Tsunetsugu's surviving corpus includes , , and a rare in the uncommon form. Among , a precious example of long with high and a single preserves the powerful late- silhouette in its original state. Across the designated works, the consistently praises blades where both and are --- sound and well-preserved --- and where the principal points of appreciation for Tsunetsugu's workmanship are fully expressed. Given the extreme scarcity of signed works, each example is recognized not only as a fine blade in its own right but as valuable reference material for understanding the art of this smith, whose output stands within the broader tradition yet retains a distinct and identifiable character.