The lineage represents one of the most distinguished sword-making schools of Kyoto (Kyō-mono), flourishing continuously from the period through the era. Tradition places the first-generation within the Ryōkai line, transmitted as either the son or grandson of Ryōkyū . He is recorded as having studied under the master Sadamune, and indeed, the technical inheritance from province is unmistakable in the school's characteristic treatment of steel. Although early tradition ascribed his activity to the Kenmu era (1334–1338), no extant dated works support so early a dating; rather, the earliest surviving inscriptions bear dates from Enbun (1356–1361), Kōan (1361–1362), and Jōji (1362–1368), and it is now the prevailing scholarly consensus that this Enbun–Jōji period corresponds to the true first generation. The school's evolution reveals a lineage of continuous activity: a successor generation active in the late period, followed by the celebrated Ōei-period masters—Genzaemon no Jō (Saemon no Jō) and Shikibu no Jō —whose works bearing Ōei and Eikyō dates established them as representative figures of the early period.
Across the successive generations, the school's collective workmanship encompasses a remarkable stylistic breadth. Two principal modes dominate the earliest generation: a refined (straight temper) reflecting the orthodox Kyoto (-school) tradition, and a -based temper directly inheriting Sadamune's characteristic manner. The forging typically shows (wood-grain pattern) mixed with (burl pattern) and areas of flowing grain, often with a tendency toward standing texture (); thickly adhering (steel particles in the ground) combine with fine (dark activity lines) and the distinctive appearance of (crystalline reflection). From the late successor generation through the Ōei-period masters, however, a third and newly prominent mode emerges: a spirited -ba (irregular temper) in which (clover-shaped) elements predominate. This -chō frequently displays a characteristic conception wherein pairs of are linked by low, small undulations, creating a rhythmically undulating temper line enriched with (streaming activity), (golden lines), and conspicuous (running mist). The (temper edge) manifests a bright, clear quality (), and the school demonstrates exceptional mastery of tōshin-horimono (blade carving)—particularly (Sanskrit seed syllables), (plain swords), (vajra-handled swords), and (ritual fire sticks), often executed in refined relief () or superimposed layers (). A notable signature feature of Genzaemon no Jō is the rendering of the character (国) with the interior element written in the form of the character (左).
The school's enduring legacy rests upon its synthesis of regional traditions into a coherent and technically sophisticated body of work. By absorbing Sadamune's innovations—particularly the rich tempering and animated —while simultaneously maintaining fidelity to Kyoto's classical tradition, the school established a versatile stylistic range that allowed successive generations to respond creatively to evolving aesthetic preferences. The late and Ōei-period expansion into vigorous represents not mere stylistic experimentation but a mature synthesis: the commanding proportions ( forms with wide and shallow ) characteristic of design are unified with sophisticated forging techniques and a tempering approach that balances animation with clarity. The school's consistent excellence across multiple generations, its documented chronological range spanning nearly a century of dated works, and its technical versatility in accommodating both restrained classical modes and flamboyant irregular patterns secure the lineage as a cornerstone of Yamashiro province sword-making and a vital conduit through which influence was transmitted into the Kyoto mainstream.