Kiyonori was a swordsmith of the Bizen Yoshii school, a branch traditionally said to have begun with Tamenori in the late Kamakura period. Although extant Kamakura-period works from this lineage are exceedingly rare, the group flourished from the Nanbokucho through the Muromachi period. Kiyonori, corresponding to the second generation in the signature compendia, was active around the Eikyo, Kakitsu, and Kyotoku eras of the early-to-mid Muromachi period, and it is recorded that he later relocated to Izumo. Dated works bearing inscriptions from Eikyo 3 (1431), Hotoku 1 (1449), and the Kyotoku era clearly establish his period of activity.

The Yoshii school's workmanship is characteristically distinguished by tempering in a ko-gunome pattern linked in a regular, continuous sequence -- described as tsure-gunome -- and by the appearance of a distinctive utsuri in which the forms of the hardened edge appear reflected directly into the ji. Kiyonori's forging shows tightly packed ko-itame-hada with ji-nie and chikei, and the utsuri stands out prominently. His hamon typically takes the form of gunome-midare running in a linked fashion, with ko-ashi and yo entering and ko-nie adhering, accompanied by sunagashi and kinsuji. The boshi characteristically turns midare-komi ending in ko-maru. Yet his range is not limited to the school's signature gunome; among his works there are also examples tempered in suguha, demonstrating the breadth of his skill.

Kiyonori's tachi display refined, slender forms with deep curvature and sakizori tendency that are particularly fine, expressing both the period character and the classical grace of the tachi tradition. In his best work, the sunagashi and kinsuji are especially conspicuous compared to his usual manner, producing a vigorous character. The dated inscriptions across multiple blades provide valuable documentary material, and the consistently high quality of his workmanship confirms his standing among the more accomplished makers of this lineage.