The school emerged in Province during the period under the leadership of the master smith , commonly referred to as Ō- or . Tradition holds that was the grandson of Sairen and son of Jitsua, with the character (左) in his signature abbreviating "Saemon Saburō." Prior to his era, Kyūshū sword production adhered to conservative methods rooted in the Yamato tradition, characterized by subdued, rustic workmanship with -toned tempering and that tended toward —a quiet, understated appearance. dramatically transformed this regional idiom, establishing a new aesthetic in which both and became bright, clear, and (keenly vivid). His revolutionary approach to refined -ba tempering, enriched with prominent and , exerted profound influence on subsequent generations of Kyūshū smiths and elevated the technical reputation of the province.
The collective technical signature of school workmanship reveals a distinctive synthesis of refinement and martial vigor. In forging, the smiths employed mixed with , often showing slight (standing grain), densely adhering , and fine threading through the steel. The demonstrates considerable variety—works may exhibit -based patterns mixed with and pointed elements, or configurations enriched with , -ba-like formations, and occasional large . Deep with thick, high-quality typifies school tempering, accompanied by internal activities such as , , , and uchi-noke. The characteristically displays vigorous with returns in pointed, forceful configurations. In , the school favored compact proportions with shallow , thin , construction, and the distinctive withered () that became a hallmark of 's workmanship. While signed are exceedingly rare—the National Treasure Kōsetsu being the most celebrated example—signed survive in comparatively substantial numbers, demonstrating the school's mastery of short-blade construction.
The school's legacy extended through numerous accomplished pupils who inherited and adapted the master's technical vocabulary. Among the prominent disciples were Yasuyoshi, Yukihiro, Yoshisada, Kunihiro, Hiroyasu, Hiroyuki, and Sadayoshi, smiths whose works are collectively designated Sue- (Later ). These successors perpetuated 's characteristic tempering enriched with varied formations, maintaining the bright, activity-filled that distinguished the school from earlier Kyūshū production. The school's influence persisted through the late period and beyond, establishing as a center of sophisticated sword production. Modern scholarship recognizes school blades for their bold magnificence, imposing -period (overall build) with wide bodies and extended large points, and the abundance of activities that overflow with fighting spirit while maintaining elegant, naturally changing configurations in both forging and tempering.