Sadatoshi (定利) is transmitted as a Kyōto smith who resided on Ayakōji around the Bun'ei era (1264–1275) of the period. His position within the Ayakōji tradition — a lineage of capital-based smiths — places him among the Kyōto-mono makers whose works are prized for their refined character and distinctive forging. The sources describe Sadatoshi as an established smith with a recognizable individual style, one whose works are sufficiently numerous and consistent to permit meaningful comparison between examples. Published references to his blades appear in Kunzan Nichinisshō, no Komeisaku, to Rekishi, and Bijutsu, reflecting sustained scholarly attention.
Sadatoshi's characteristic forging is an , at times with a slight (flowing) tendency, in which are visible and is abundant. Both the and the hardened edge retain what the describes as an archaic, old-style taste — termed in character. His is a composition of mixed with , and the characteristically takes on an — a moist, softly diffused quality — that is identified as a distinguishing feature of this smith. In certain works, the is noted as being especially bright and clear relative to his broader output. The may show a tendency toward becoming disordered (). The is sometimes broader and set higher than is ordinarily seen among his peers, and the curvature can vary, with some displaying shallower than is typical. While (grooves) are occasionally encountered, of other types are described as uncommon on Sadatoshi's works.
The evaluations consistently emphasize that Sadatoshi's works "clearly express the characteristic features of this smith," with the archaic and composition and the quality of the serving as reliable points of attribution. His blades are valued both as accomplished works of the Kyōto tradition and as documentary material for the Ayakōji school, a lineage where securely signed examples carry particular scholarly weight.