Sadatsugu is regarded as a representative smith of the Aoe school, working in the lower basin of the Takahashi River in Bitchu Province. The name Sadatsugu was inherited across generations, with smiths bearing this name continuing from the early Kamakura period through the Nanbokucho period. The NBTHK observes that among works bearing the name, there are "examples with a small manner of signature, examples of ordinary proportion, and others that appear somewhat later in date; accordingly, it is thought that 'Sadatsugu' does not refer to a single individual." Works through about the middle of the Kamakura period are categorized as Ko-Aoe, while those thereafter through the Nanbokucho period are broadly grouped as Aoe, the two being distinguished in this manner.

Sadatsugu's forging is marked by tightly worked ko-itame mixed with mokume, producing the characteristic chirimen-hada ("crepe-like grain") associated with Ko-Aoe workmanship. The ji-nie adheres well, with abundant chikei and a patchy utsuri-like effect appearing in finer examples. The hamon is founded on suguha into which a modest amount of ko-gunome is blended, tempered in nie-deki or nioi-dominant modes with accompanying ko-nie; sunagashi and kinsuji run through. The boshi is characteristically straight, turning back in a rounded manner. Signatures are cut in two characters on the ha-ura, near the mune side, described as "an unrestrained, fluent inscription executed in fine chisel work with the addition of gyaku-tagane" (reverse chisel strokes), while the large o-sujikai file marks likewise display characteristic features of Aoe work.

The NBTHK consistently praises these works for their archaic dignity, noting that the "orderly suguha into which suitably measured ko-gunome is blended -- together with the excellent quality of the jigane and the calm, gentle sugata -- combines to convey the dignity characteristic of the Aoe school in a single piece." Sadatsugu's finest works invite comparison with National Treasure-class examples, with one Tokubetsu-Juyo tachi said to closely resemble the National Treasure tachi transmitted in the So Count family of Tsushima. Within the broader Aoe lineage, Sadatsugu stands as the name most firmly associated with the school's highest achievements, embodying the refined suguha tradition and distinguished forging that secured Bitchu swords their ancient reputation.