Nagasada signed himself Okatsuyama-roku Fujiwara Nagasada and gave his personal name as Matsui Jiichiro. He was born in Bunka 6, the year 1809, in Fuwa District of Mino Province, the son of Matsui Naosaburo, and the published record traces a working life that moved across three provinces: for a time he served the Tokugawa house of Kishu as an official smith, around Man'en 1 he forged at Tamaru in Ise, and from about Bunkyu 2 he settled at Aoyama in Edo, where he made swords until his death in Meiji 2 at the age of sixty. The place-name Okatsuyama that recurs in his signatures refers to a locality north of Omotesa in his native district, the place from which he took his swordsmith's name. His dated blades fall within the closing years of the Edo period, a katana of Keio 1 finely forged at Edo among them, and they place him squarely in the shinshinto revival rather than in the Sue-Seki of the old Mino tradition from which his school name descends.
His characteristic hand is a bold, broad-bladed katana built to the heroic proportions the late-Edo smiths favoured: a wide mihaba carrying little taper from base to tip, a thick kasane, a shallow sori, and an extended chu-kissaki, the whole given a stout and magnificent bearing. Set over this construction is a flamboyant gunome-midare into which large gunome, round-headed gunome, small gunome and occasionally pointed elements are mixed. The published sources describe the pattern as華やかに乱れ, a brilliantly animated midare, with ashi and yo entering vigorously, the nioi deep and the nie adhering well and evenly, some of it coarser; over and through the temper run frequent sunagashi, kinsuji and long nie-suji, and the nioiguchi is bright. One feature is so constant across his recorded work that the judges single it out: the mitsu-mune back, a three-surface ridge that one of the published commentaries names as この工の見どころ, the point of interest particular to this smith[[c:1]].
The jigane beneath that temper is a close itame, drawn tight and at times mixed with ko-itame and mokume, over which the ji-nie lies thick and fine chikei enter; on the longest of the recorded blades the grain stands a little open toward the koshimoto, but the prevailing impression is of a dense, well-forged jigane. There is no utsuri here, as there would be in a Bizen or Yamashiro ji; the brightness of his work comes instead from the depth of the nioi and the evenness of the nie. The boshi answers the temper below it, running straight or with a shallow notare and turning back in ko-maru, the very tip swept into hakikake, and on occasion tempered deeply through the yokote with a returning kaeri; one blade shows tobiyaki and muneyaki where the hardening spills onto the back near the monouchi. The nakago is ubu on every example, finished with a ha-agari kurijiri and o-sujikai file marks dressed with kesho, and carries the long signature that gives his full style and, on the reverse, the date and the place of forging.
The corpus that survives in the designated record is uniform in manner, all of it signed katana of his Edo maturity, so that his work is read less through phases than through one perfected idiom seen at full strength. Within it the judges draw a register of intensity: the most brilliant pieces, those they call出色 and華やかな, press the large and round-headed gunome and the deep nie to their flamboyant extreme, while quieter examples hold the same elements in a tighter midare. The horimono on two of the blades, the characters Hachiman Daibosatsu cut on one omote and gomabashi on a ura, belong to the same votive and martial taste that runs through bakumatsu work. The governing question the published sources return to is not of date or generation but of resemblance, for his manner sits so close to one famous neighbour that the eye must be told how to part them.
That neighbour is the Kiyomaro school. Repeatedly the commentaries state that his bold sugata, his nie-deep gunome-midare and his profuse kinsuji and sunagashi could be mistaken at a glance for Kiyomaro's line, 清麿一門に見紛う in the recurring phrase[[c:2]]. The distinction the judges then draw is exact, and it is the heart of his kantei. Within the ha one does not find the choji-tinged elements or the angular gunome that the Kiyomaro group habitually shows, 丁子がかった刃や角ばる互の目などは見られず[[c:3]]; in their place the large gunome and the round-headed gunome stand out, occasional pointed teeth enter, and the boshi turns back with a rounded tip rather than running pointed. By those features, together with the frequent mitsu-mune, the published sources separate his hand from the lineage it most resembles. He stands, then, as an independent bakumatsu master who carried the Kiyomaro manner without belonging to it, a Mino-born smith working the revival idiom for the Kishu Tokugawa and then in Edo.
Nagasada is an uncommon name on the designated record. Five of his katana are held at Juyo Token, all of them signed, and none has been raised to a higher designation; provenance is recorded for one, which passed through the hands of Sato Yoshitoi. These are the blades a private collector might realistically hope to encounter, and they reach the market only from time to time and with patience, a designated katana of his appearing as a notable event rather than a regular offering. The judges' own summations give the measure of why they are sought: of the Keio 1 katana made for Nishibori Mitsunori, the published record says the workmanship in both ji and ha is exceptionally fine and the piece may be termed 代表作と称すべき, a representative work of the smith[[c:4]]; of another it notes that the deep nioi, the evenly adhering nie and the bright nioiguchi are especially worthy of remark; and of the most robust it observes that the large-scale bearing and the flamboyant temper together convey a powerful presence. A signed katana by Nagasada offers, in a single late hand, the heroic shinshinto sugata and the nie-laden Kiyomaro-school manner held just short of Kiyomaro himself.
