At Hamachō in , in the closing decades of the eighteenth century and the opening ones of the nineteenth, Suishinshi Masahide gathered the school that would turn Japanese swordmaking back toward its medieval models. Born Kawabe Gihachirō at Akayu in Dewa in 1750, signing first as Suzuki Takahide and then Eikoku, he studied under the Shitahara smith Yoshihide of , took the name Masahide in An'ei 3, and served the Akimoto house of before settling in , where he worked for nearly fifty years. He is the founding figure of the and the theorist of the fukko-tō (revival-sword) doctrine, the argument that the sword ought to return to its forms. Around that teaching he drew a large body of pupils, among them Naotane, who would give the revival its fullest practical form, the future second Masayoshi (Hosokawa Morihide), and a wider and provincial following that carried the program into the Mito, Yonezawa, Tsuyama, and Tatebayashi domains.
The shared vocabulary of the school is the deliberate reach back into the traditions, worked over a tightly forged, often -toned with thick . Masahide's own prime hand was the Ōsaka-, the surging tōran-midare of Tsuda Sukehiro opening from a long and the broad after Inoue Shinkai, betrayed on even his closest copies by a blackish, coarse that spills from the into the . Naotane gave the revival its and faces: a reverse-leaning with angular and , modeled on the late- masters Kagemitsu and Kanemitsu and anchored by a consciously revived that no ordinary steel carries, set beside a with its whorled uzumaki- and coarse, striped . The pupils divided this inheritance along their own lines. Jirōtarō Naokatsu, Naotane's adopted son, took a - led by a from Kanemitsu with a pervasive slant and - or in the . Suishinshi Masatsugu reproduced Naotane's two traditions, and , down to the cut of his signature. Through Masayoshi the current passed to his heir Hosokawa Masamori of Tsuyama, whose clusters mixed with gunome-chōji and . The Osaka wave traveled separately into Mito through Naoe Sukemasa, who set a Shinkai-styled and a Sukehiro tōran over a clear , while Chōunsai Tsunatoshi of the Uesugi service carried a mixed with , , and tōran-midare, often with carving by his own hand.
To the school is to weigh a tradition consciously copied against the period marks the copy cannot shed: the constant of the line is that the is never the pure of old but carries throughout, a difference the names outright as the divide between and . The revived in Naotane and Naokatsu, the spilling in Masahide, the whorled uzumaki- shared across the line, and the broad, thick- late- are the surest tells, narrowed further by the school's habit of full, dated signatures that make these smiths among the most exactly knowable of their age. Masahide stands at the head as the teacher and theorist, his finest work in his Ōsaka copies rather than the doctrine he proclaimed; Naotane stands ahead of him in execution, his - held the finest among the . Their pupils define the late- and revivals as practiced through and the domains, with Naokatsu and Masatsugu read as the next hands after Naotane and Masayoshi. The provenance of the school runs through domain commission and bestowal (Mito blades forged at the Kōrakuen by lordly order, Tsuyama and Yonezawa fief work, Naotane's Sanada and an Imperial-collection ) rather than ancient transmission, fitting for a movement that, within a single generation at , redrew the direction of nineteenth-century swordmaking by turning it back toward the old models.