The Ōmori school was one of the great (town-carving) lineages of , founded in the first half of the eighteenth century by Ōmori Terumasa (大森英昌, also read Eishō), a direct disciple of Yokoya Sōmin. It was Terumasa's nephew and successor, Ōmori Teruhide (大森英秀, also read Hideshū; 1730–1798) — personal name Kisōji, art name Ryūusai (龍雨斎) — who raised the house to eminence: the repeatedly characterize him as "a celebrated master who brought renewed prosperity to the line," one who "built one of the most influential branches within the Yokoya school." A dated of Meiwa 7 (1770) anchors his mature activity, and the workshop remained rooted in the shogunal capital throughout its history — his pupil Hidetomo proudly signed works "Tōto, by the Sumida River" (東都隅田川辺). The headship then passed through Hidenaga to Hidemitsu (英満), Teruhide's fifth son, carrying the line deep into the late period.
The school's shared vocabulary rests on worked with a (fish-roe) ground, carved in (high relief) and enriched with inlay and polychrome in gold, silver, , , and the scarlet copper hiirodō; favored subjects were "shishi, animals, birds, flowers, and figural scenes." Its defining invention is the strikingly three-dimensional wave design known as Ōmori-nami (大森浪), the "Ōmori waves," together with sunago-zōgan gold-dust inlay executed in the manner and the flush gold inlay evocative of lacquer called nashiji-zōgan or chirigami- — techniques devised, the state, to heighten the elegant, courtly taste of the work. The judges single out "the weighty carving characteristic of the Ōmori style," deployed across a repertoire spanning peony-and-shishi compositions, birds of prey amid rising and surging waves, tigers in bamboo, waves with myriad fish (), the vanguard crossing of the Uji River, Fan Kuai at the Banquet at Hongmen, and the treasure ship of the Seven Lucky Gods. Later generations show measured evolution: Hidemitsu "preserved the carving methods of his forebears while accepting changes in contemporary taste," turning also to iron grounds in and collaborating with the painter Kanō Dōhaku Aishin, whose preparatory drawings attest to exchange with the painting ateliers of the day; substitute works () by his disciple Ōmori Mitsutoki under the master's signature reveal a flourishing workshop practice.
The school's standing is confirmed at the highest levels of patronage: a ceremonial hosodachi mounting transmitted in the Ii family of Hikone, its entire suite of fittings by Teruhide with the clan's tachibana crest in and gold , documents the Ōmori masters as makers of ceremonial equipment. From the atelier radiated an exceptionally influential teaching lineage: Hidetomo (Ryūrinsai Ōmori Sadabei), recorded in the Kinkō Meifu as "a foremost disciple of Teruhide"; the Mito-branch Moriyama retainer Otsuzuka Hisanori, whose "dense, richly wrought inlay reached a uniquely individual realm" and drew praise in the Natsuo Chōkin-dan; Horie Kōsei, who entered the Ōmori school after Hamano Masayuki's death and later, as retained craftsman of the Hachisuka family of Awa, "trained many pupils of his own school"; and Izumi Hidetoshi, who studied under both Teruhide and Hidetomo. Through these channels the Ōmori manner — above all its sculptural waves and sumptuous relief — passed into the broader current of late- metalwork, securing the school's place as one of the most powerful branches of the Yokoya tradition in the tosogu canon.