Sadatsugu is among the most celebrated names of the school of Province, a lineage whose reputation was already established when the eleventh-century travelogue Sarugaku-ki singled out "the swords of " as notable products. Since the Kanchiin-bon Meizukushi, Sadatsugu has been transmitted as one of the swordsmiths selected to serve Retired Emperor Gotoba as an appointed . The Shinkan Hiden-sho accords him the highest valuation among work -- "supreme: fifteen " -- and he has long been regarded as first-rank even among smiths. The name was inherited in unbroken succession from the early period through the late period, and blades bearing this signature may be regarded as belonging to one of the representative houses of the school.
Works attributed to Sadatsugu display the cardinal features of craftsmanship across his successive generations. The forging characteristically shows a tightly packed with extremely fine thickly applied, fine , and patches of mottled -like texture, while the grain tends to stand, at times producing a (crepe-like) appearance or becoming -inclined. The is further distinguished by -- appearing as or streak-like -- and areas suggestive of . The is predominantly -based, ranging from with tight to mixed with , , , and elements; and enter well, with intermingled, while fine and appear throughout. The typically runs with a shallow tendency, turning back in or approaching .
Within scholarship, Sadatsugu occupies a singular position: from early times there has been a tendency to attribute unsigned works -- when they show a typical style and are of particularly good workmanship -- to this name, in the sense of designating them "a representative superior work of the school." The repeatedly observe that both and are bright and clear, that the is bright, and that the internal are plentiful, creating a lively effect. Works ranging from the late through the mid- period are praised for conspicuously expressing the characteristics of the group, and blades displaying reverse-slanting elements in the temper are noted as forerunners to the splendid - that flourished later in the period.