Sadakiyo belongs to the Hosho group of Yamato Province, one of the five classical Yamato traditions, which resided in Takaichi District and flourished from the late period into the period. According to the (sword signature references), Sadakiyo is recorded as a son of Sadamune, and his working period is placed around the Genko era (1321–1324), though some sources alternatively record him as a son of Hosho Kunimitsu, and it is considered likely that there were smiths of the name across generations. He stands among the accomplished makers of the lineage alongside Sadamune, Sadayoshi, Sadaoki, and Sadamitsu, all sharing the character "" (貞) as a common element in their names — a hallmark tsuji of the Hosho group. The consistently identifies the Hosho school as the tradition in which individuality of style is most conspicuously evident among the five Yamato schools.
Sadakiyo's forging is a thoroughly — the all-over so- structure that is the defining technical signature of the Hosho lineage — densely worked, well refined, and compact. Thickly applied and abundant characterize the , with appearing in finer examples. The is a -based temper, frequently becoming markedly along the , displaying vigorous activity in uchi-noke, , , and even sanjuba, together with and . The is deep, adheres well, and the is consistently described as bright and clear (). A recurring structural observation notes that the hardened width broadens from around the upward, with becoming one step stronger in that region. The is vigorously finished with and terminates in — another hallmark of the school. On the , file marks and a bluntly cut-off tang tip are characteristic. Signed works bearing the "Fujiwara" honorific are only sparsely encountered overall, though in Sadakiyo's case they are seen with some frequency. His signature characters tend to be linear, with conspicuous reverse-chisel strokes, a mannerism shared among the smiths of this group. Extant works appear in two types: somewhat larger, robust examples of imposing build, and comparatively smaller pieces typical of Sadaoki's usual manner.
The appraisals repeatedly affirm that Sadakiyo's work displays the characteristics of the Hosho school so fully that nothing is left to be desired, and that his finest pieces should be termed representative works not only of this smith but of the school as a whole. The various smiths of the Hosho group do not present sharply differentiated personal individuality, yet Sadakiyo's output is acclaimed for both workmanship and state of preservation. His signed pieces are described as exceedingly few and precious, with no dated examples yet observed, lending particular scholarly weight to each authenticated work. Within the broader Yamato tradition, the Hosho group's emphatic forging, -laden , and vigorous constitute a technical idiom of the highest individuality, and Sadakiyo stands as one of its most accomplished representatives.