Tsunetsugu is one of the representative smiths of the school of , the older that forged along the lower Takahashi river in a province the records praise for its swords from the close of the period. The published sources name him plainly: "Tsunetsugu is a representative smith of " (恒次は古青江の代表工), held by one tradition to be the son of Moritsugu and the younger brother of Sadatsugu, and counted, the commentary writes, "together with Sadatsugu and Tsugiie among the of the Retired Emperor Go-Toba" (貞次・次家と共に後鳥羽院番鍛冶に数えられている). The name is not that of a single hand. Judging from the manner of signing, the reckons there were "two or three of the name within " (古青江にも二、三の同名), and elsewhere that "several smiths worked through the period" (鎌倉期を通じて数工) under it, so the published record treats Tsunetsugu as a representative name carried as a mainstay of the forge from the opening of down into the , rather than as one biography. Among the Tsunetsugu-name stands the Juzumaru, one of the Tenka-Goken, famous as the protective of the priest Nichiren, and the published commentary notes that this raises the name higher still.
His is the calmest of the early hands. The signed read on one consistent manner: a -based that the published sources describe as "a tone running shallow with a moist tendency" (直刃調に浅く濡れごころ), faintly undulating, with and at times mixed in. and run into it constantly, and the is strong and well laid, with sweeping through and appearing in places. The answers the temper, going straight and turning back in a small . It is a quiet, even temper, the least flamboyant of the quartet, and its discipline is the first thing that marks his hand: where the brethren let the run, his stays close to the line, the activity carried inside it as , and the occasional rather than along its crest.
The is the steel, and the published record dwells on it: of one signed the writes that, the activity within the aside, "the in particular is splendid" (特に地がねが見事である). It is a that stands a little, mixed with , working up to the crepe-like surface the sources call (the is recorded as "showing a tendency", 縮緬風を呈し). Fine gathers across it and enter. On many blades the iron is broken by and the clear patches the school knew as , and a faint rises in it, on the pieces a and, on the broader late work, standing in streaks toward the . A reverse tendency surfaces on a minority of blades, and even - mixed on the , a within-school tell that runs quieter in him than in his brethren. The whole is the speckled, deeply flavored the calls character, "quiet in tone, yet possessed of deep interest and savor" (地味ながら味わいの深い同派の作風).
The work falls into two registers that the published descriptions keep distinct. The first is the signed core: comparatively small or lightly shortened in with and a , carrying a thick-chiseled two-character signature, the chisel-work so heavy the calls strokes of this boldness rare. The placement is itself a point, for the published commentary records that the signature falls now on the , now on the , and observes by way of reference that within the line descending from Masatsune signs on the front while the Sadatsugu group cuts to the back. The second register is the and work attributed to the name, read as later Tsunetsugu: a bearing a red-lacquer " Tsunetsugu" attribution beside a -era Kotsune , and the two unsigned Bijutsuhin blades, one judged late , one , which mark the later end of the line. Against this the is candid that the multiplicity of hands leaves questions: of one signed it allows that there is "some doubt regarding the inscription, leaving room for further study".
The published sources are equally careful to keep him apart from his homonyms. The commentary that praises his notes that "the name is found among the group as well" (古備前派に同名があり), both reckoned skilled, and the appraisal of the pieces is steadied by their own evidence rather than by the name alone: the file marks the calls the prescribed convention, the bold thick-chiseled two characters, the speckled and in the , and the disciplined with its reverse-tending . His are placed against the wider field by these grounded marks, not by contrast with another school: the calm of his temper, the crepe-like and the bold signature set his work apart, and the records read the hand across the early to span the name covers.
Fujishiro grades Tsunetsugu Jo-jo , and the Toko Taikan values his work among the upper rank of the early names. The designations behind the name sit high: one of his is , with seven at , three Important Cultural Properties, and two prewar Bijutsuhin among the unsigned work. No blade under the code is a National Treasure, so the patrimony preserved in trust is the three Important Cultural Properties, while the tradeable standing rests on that and the tier. The provenance roll is notable for so old a name: blades carry histories through the Kishu Tokugawa family, the Uesugi family, the Tsuchiya family, the Arima family, and the Imperial Family down to the Emperor Meiji, and the Kotsune of 8 fixes the 's appraisal in the seventeenth century. Of recorded whereabouts a handful are held in public institutions and a shrine, with others in long-private hands. A signed Tsunetsugu reaches the market only rarely; when one of the or blades does appear it is a landmark for the collector of the older schools, encountered with patience rather than sought, and the Juzumaru itself, a designated cultural property held in trust, is never among them.