On the tang of a broad katana now in the thirty-seventh Jūyō session, below the mekugi-ana toward the mune, runs a long signature reading Echizen no Kuni Shimosaka Sadatsugu, and on the reverse a tachi-aoi crest is cut above the added inscription Jūdō oyobi tabitabi massai ken kore nari, the cutting-test boast that this sword has severed stacked bodies and is a blade for the latter age. That combination of marks fixes the smith. Sadatsugu is the first-generation Echizen Shimosaka Hyūga no Kami Sadatsugu, an early Shintō maker of the Yasutsugu milieu in Echizen Province. No dated work by him has yet been seen, and the published sources place him at no later than the Keichō era on the evidence of his workmanship and the manner of his signature alone. They read him as one of the most influential close associates of the first-generation Yasutsugu, the head of the Echizen Shimosaka group, calling him 'one of Yasutsugu's most influential near attendants'[[c:1]]: his Shimosaka signature closely echoes Yasutsugu's own, his blades carry the same massai-ken inscription, and like Yasutsugu he was a favored smith of Honda Hida no Kami Narishige, the senior hereditary retainer of the Echizen house whose tachi-aoi crest[[c:2]] appears cut on the tang.
What the published sources return to, blade after blade, is the prominence of his chōji. They state that among the numerous smiths of the Echizen-Seki group his point of especial interest is precisely this, 「丁子が目立っているところにその見どころが窺える」, and on another katana, set directly against his model, that 「丁字が目立つ刃文に貞次の個性がうかがわれる」, that it is in a hamon where the chōji stands out more conspicuously than Yasutsugu's that Sadatsugu's individuality is perceived. His temper is a chōji-midare taken as the principal theme, mixed with gunome, gunome-chōji and pointed togariba, and in places a slightly shima-ba-like detachment. Long ashi enter vigorously, sometimes thick, with yō intermingled, the nioi deep, the nie adhering well and clustering into uneven passages, and through the steps of the midare run fine kinsuji and sunagashi. Tobiyaki appears across the ha, the crescent-moon-shaped variety that the published sources note is also met with in Yasutsugu's work, and around the monouchi muneyaki shows along the back. The nioiguchi tends toward shizumi, subdued and at points roughened, a quiet band beneath a busy temper.
His jigane is an itame mixed with mokume that stands and opens, tending to flow into nagare, the hada conspicuous overall rather than tight. Over it ji-nie adheres and fine chikei enter, and the steel carries a blackish cast that the published sources call kitaguni-mono-like, 「北国物らしい肌合を示し」, the dark provincial jigane of the Hokuriku country. It is this somber, active ji, descended through the many Echizen-Seki smiths from the Seki tradition, against which the chōji and the kinsuji of the ha are thrown into relief. The bōshi answers the temper below it: a midare-komi that turns in with a sharp or rounded point, the kaeri deep and long, brushing into hakikake, and on one blade crossing the yokote in gunome before it returns. Where the omote runs straight to a ko-maru the ura is read as showing a sanpin-like, Mishina-tinged flavor, the inheritance of the Echizen-Seki line surfacing in the point.
Within so small a designated body the published sources still draw a quieter register. On the earliest of his Jūyō katana the upper half of the omote becomes a suguha-toned temper mixed with gunome, with tobiyaki appearing, while the rest opens into chōji-midare with ashi and sunagashi, the temper at its calmest coming close to the restrained Yasutsugu manner before the chōji reasserts itself. The carving is the other constant. His blades carry kinai-bori of ume and take in the Echizen Shimosaka manner, and on the latest piece the published sources describe a composition that takes as its reference the ume-and-bamboo carving of a famed hira-wakizashi attributed to Sadamune and expands it across the whole blade of a stoutly built sword, with the tempering fired into a brilliant, animated midare so as not to be overwhelmed by it, the whole 「一際賑やかな作品に仕上がっている」, finished into an especially lively and bustling work. That no two of his five designated blades carry a date keeps his chronology a matter read from the steel rather than written on the tang.
He is placed by the line itself rather than by an independent reputation. The published sources name his hamon as descended from the Seki tradition and his steel and uneven nie, with the ura bōshi showing a sanpin-like flavor and the darkish kane, as well expressing the characteristics of this group, the Mishina-tinged manner of the Echizen-Seki smiths. Against that shared jigane his own tell is the chōji, the feature they repeatedly contrast with Yasutsugu's quieter temper, and the kinai-bori, the massai-ken inscription and the Narishige crest, the documentary marks that bind him to Yasutsugu's circle. His individuality, as the published commentary frames it, is not a departure from the Echizen Shimosaka idiom but the brightest and most chōji-laden expression of it, a smith who worked at Yasutsugu's side and tempered a more animated midare than his master.
Sadatsugu is rated Jō-saku in the Fujishiro ranking, the mark of a sound master rather than a great name. Five of his blades hold the rank of Jūyō-Tōken, with no National Treasure or Important Cultural Property among them and nothing in the higher Tokubetsu Jūyō tier, so his record is that of a respected provincial Shintō smith of the Yasutsugu group. Provenance beyond the Honda Narishige patronage read from the crest is thin in the designated record, with no daimyō house or museum named among his blades, so the honest account is of a body held quietly in private hands. For a collector his work is among the rarer encounters of the Echizen Shintō makers. Only five katana stand on the official record, every one of them signed, which fixes the name with a certainty that mumei attributions cannot, and a signed Shimosaka Sadatsugu of this quality comes to light only from time to time and with patience, a landmark of the Yasutsugu circle when one does.
