Tsunetsugu is one of the representative names of the school of Province, a lineage whose origins trace to the earliest strata of Japanese swordsmithing tradition. The earliest Tsunetsugu is traditionally held to be the son of Moritsugu and the younger brother of Sadatsugu, and he is counted — together with Sadatsugu and Tsugie — among the (appointed swordsmiths) summoned to serve Retired Emperor Go-Toba. The name was transmitted as a mainline within the school from the early period through the era, and it is thought that within there were two or three smiths using the name at approximately the time, their calligraphic styles varying widely. Tsunetsugu's renown is elevated still further by the existence of the celebrated Juzumaru Tsunetsugu, famed as the protective sword of Saint Nichiren. A distinct smith bearing the title no Sakon Shogen Tsunetsugu emerged in the late period, with an extant dated work from Genko 2 (1322) establishing his period of activity; however, signed works by this Tsunetsugu are few. Additionally, a Saemon no Jo Tsunetsugu was active in Manjusho, Province, with a dated inscription of Enkyo 3 (1310), and it should be noted that the clear distinction between the Tsunetsugu and the Sakon Shogen Tsunetsugu belongs only to the modern era.
The workmanship of the Tsunetsugu lineage divides broadly into two tendencies: pieces fundamentally based on , and those in which and stand out conspicuously. Tsunetsugu works characteristically display mixed with , the grain standing finely to produce a (crepe-like texture), often with intermixed. The is typically with adhering well, and activities such as , , , and appear throughout. A distinctive — sometimes leaning in reverse fashion, sometimes mottled as , and occasionally appearing in tiered bands suggestive of — stands out in the . In later and -period work, the becomes calmer, the tightens, and the overall appearance becomes bright and clear. Compared with contemporary works, these blades present what the describes as "a quieter, more restrained and astringent character," with vigorous hardening activity within the tempered area that distinguishes them from contemporaneous production. File marks of and signatures cut with a characteristically thick chisel strongly express the distinctive identity of the group.
Across the designation records, the Tsunetsugu name recurs with evaluative phrases that confirm the lineage's enduring scholarly importance. Works are praised for their condition — "sound and well-preserved" in both and — and for retaining excellent (flesh), lending them "a substantial and forceful presence." The repeatedly affirms that individual pieces "superbly manifest the aesthetic strengths and points of interest characteristic of bright, clear work," and notes workmanship that is "quiet in tone, yet possessed of deep interest and savor." The is singled out as "especially splendid," and blades are recognized for showing "diverse variation" in the forging and "plentiful activities" within the that together "create a profound flavor." examples with their dignified form, high , and original inscriptions recording residence and official title are valued as reference material of high documentary significance. Taken as a whole, the Tsunetsugu lineage stands as a pillar of the tradition — its long transmission, its association with imperial service, and its technically distinctive workmanship securing it a place of enduring consequence in the study of Japanese swords.