The tradition originated in Province during the late period when Kaneuji—originally of the Yamato school—relocated from his studies under Masamune of to the village of in Tagai District. Taking the place-name as his appellation, he became known as Saburō Kaneuji, and established a lineage that would become one of the most celebrated branches among the so-called Masamune Jittetsu (Ten Great Disciples of Masamune). While Kaneuji himself is often considered the paramount master of this group, the designation "" came to be applied broadly to unsigned works displaying the characteristic manner of this school, encompassing not only Kaneuji but also his contemporaries and successors working within the stylistic orbit. A related category, Yamato , refers either to Kaneuji's early production before settling in —when his work retained stronger Yamato characteristics—or to smiths of the Kanetsugu lineage who remained in Yamato rather than migrating to .
The collective hallmarks of workmanship reveal a distinctive synthesis of Sōshū-den brilliance and Yamato structural sensibilities. The forging typically displays flowing mixed with , frequently tending toward (standing grain), with areas where inclinations appear along the edge. A defining feature is the dense application of fine , often described as thickly adhering, accompanied by abundant that enter repeatedly to produce a notably clear and bright appearance. The favors shallow as a foundation, mixed with , , and pointed elements (), forming compositions that range from gentle undulations to boldly disturbed patterns. The temper is richly -based, with vigorous streaming through the pattern, frequent , and in many examples a "wet" quality () within the tempered area. Characteristic activities include along the , occasional (double-temper) effects that recall Yamato influence, and in some works the presence of linked sequences. The commonly enters in or , turning back with pointed or rounded forms, and frequently displays at the tip.
Among the upper tier of Sōshū-den productions, works attributed to the lineage are particularly valued for the way their gleaming activities create patterns that are both vigorous and refined. The thick and prominent in the forging, combined with the bright, clear in the temper, result in blades that are described as —possessing a luminous clarity that distinguishes superior examples. While the style stands closest to Masamune among his disciples, the manner retains its own individuality: the blending of Yamato characteristics into the tradition produces a distinctive temperament in both and that connoisseurs recognize at a glance. Many extant examples survive only as greatly shortened () and unsigned () blades, yet the workmanship in such pieces typically remains sound and well-preserved (), testifying to the fundamental excellence of forging and tempering that defines this celebrated school.