Sadatoshi was a swordsmith resident at Ayakoji in Kyoto, traditionally regarded as the founder of the Ayakoji school — one of several Yamashiro-den lineages, alongside the Awataguchi and Rai, active during the Kamakura period. Sword reference works generally place his production around the Bun'ei era (1264–1288), and one persistent tradition holds that he enjoyed close relations with Rai Kuniyuki, even transmitting that "depending on the state of demand, they produced substitute works for one another." However, the NBTHK has consistently observed that when extant works are surveyed as a whole, Sadatoshi's manner "follows the sphere of the old Kyoto makers of the Sanjo and Gojo groups," possessing "an archaic elegance that calls to mind Awataguchi Kuniyasu." From these features, the board repeatedly concludes that "his dating should be placed earlier than the commonly accepted view," and that if contact with Kuniyuki occurred at all, "it would most plausibly fall at the end of Sadatoshi's career and the beginning of Kuniyuki's."

Sadatoshi's tachi characteristically display a slender build with pronounced taper from motohaba to sakihaba, high koshizori with funbari, and a ko-kissaki — presenting what the setsumei consistently term a "classical and graceful tachi-sugata." The kitae is a densely forged ko-itame with thickly adhering ji-nie, fine chikei, and prominent nie-utsuri; old transmission texts describe the steel as appearing "viscous and sticky" (toromekite nebaki yo ni mietari), a phrase the NBTHK cites approvingly, and several examiners note an overall nettori ("sticky") texture. The hamon is the school's most distinguishing signature: a suguha-based temper mixed with ko-choji, ko-gunome, and ko-midare in which "the intervals of the undulations are close and form a complex, small-patterned midare." At the yakigashira, still smaller patches of temper and yubashiri appear "in dotted succession, forming a nijuba-like effect," while the nioiguchi characteristically "tends toward urumi" — a moist, soft quality that serves as a primary diagnostic trait. The boshi typically finishes with hakikake, at times assuming a flame-like (kaen) appearance. Internal activities are rich: kinsuji, sunagashi, and tobiyaki appear frequently, contributing to what the board describes as "an archaic and refined taste."

Across four decades of designation proceedings, the NBTHK's evaluative language for Sadatoshi remains remarkably stable. His works are praised as "archaically elegant and richly flavored with depth of interest," possessing "notably high dignity" in both jihada and hamon. Signed examples receive particular notice for their documentary value — "precious material for research into Sadatoshi's style" — with the distinctive two-character inscription, in which the character "Sada" is cut large and "Toshi" comparatively small, itself serving as an attribution marker. The board repeatedly situates Sadatoshi not among the mid-Kamakura Rai contemporaries with whom tradition pairs him, but rather as a direct inheritor of the earliest Kyoto forging lineage, carrying the Sanjo and Gojo manner into a period of transition. Several designated works bear distinguished provenance — the Kishu Tokugawa house, the Shimazu of Sadowara, the Meiji statesman Ito Miyoji — and at least one blade preserves a kirikomi on the mune that "conveys the blade's martial exploits of old." In sum, Sadatoshi occupies a singular position within the Yamashiro tradition: a smith whose archaic craftsmanship bridges the oldest Kyoto schools and the emerging Rai lineage, and whose tightly woven, urumi-tinged tempering remains among the most immediately recognizable idioms in the classical sword canon.