The school (伊藤派) was a prolific kinkō lineage based in Kanda, , in province. The line was established by Masanaga (正長, d. 1727), who received appointment as official maker (kōgi o-kakae tsubashi) to the Tokugawa Shogunate following an audience with Shogun Ienobu in 1710. Successive heads bore the character 正 (Masa-) in their art names, producing ten recorded generations from the Genroku era through the Meiji period. The second-generation master Masatsune (正恒) developed - (糸透かし), the school's signature technique of extremely fine saw-cut openwork. The tenth and final head, Katsumi (伊藤勝見, 1829--1910), originally named Masataka (正隆), entered the school of Tanaka Seiju (田中清寿) at twelve, was adopted into his master's household at seventeen, and received the rank of Hōkyō (法橋) while still young, together with the art name Tōryūsai (東竜斎). After parting ways with Seiju, Katsumi studied under Shibata Zeshin (柴田是真), and in Man'en 1 (1860) was adopted into the Masahiro family, becoming the tenth-generation head. This dual formation -- kinkō discipline under the Tanaka lineage and lacquer refinement under Zeshin -- profoundly shaped the school's late output.
The school's collective style is characterised by mastery of (象嵌, inlay) and (色絵, polychrome metalwork) deployed with what the repeatedly describe as precision and accuracy. Works are executed on plates of iron, (四分一), (朧銀), or (赤銅), frequently with (魚子地) grounds. The technical repertoire encompasses (高彫, high relief), (鋤出高彫), (片切彫), fine (毛彫, hairline engraving), suemon-zōgan (据文象嵌), and (布目象嵌), often combined within a single composition. Masatsune's work employs shippō (七宝, cloisonné enamel) on iron plate, as seen in a unified signed "Bushū-jū Masatsune" whose , , , and are coordinated as a single aesthetic programme with (螺鈿, mother-of-pearl) and gold uchikomi (打込) work. Katsumi's mature output favours figural and narrative subjects: the Frog Battle after the celebrated Chōjū-giga scrolls attributed to Toba Sōjō, Gama Sennin with his toad beneath a willow, and Daisē Fudō Myōō realised with emphatic devotional presence. The praise his outstanding carving skill and superb polychrome inlay as revealing "Katsumi's true strength." Botanical subjects -- peonies with butterflies -- also appear, executed in (色金) including gold, silver, hi-irodō (緋色銅), and brass, with "particularly fine coloration."
The school occupies a distinctive place in the canon as a -based lineage that sustained high-level production across the entire period. Its works were widely disseminated through the sankin-kōtai system, as samurai from all provinces acquired during their attendance in . In Katsumi, the school's final master, the recognise an artist of consummate technical command whose works "elevate comic, satirical subjects into fully realized works of art." That his depicting the Chōjū-giga Frog Battle is described as a "forceful work from his later years" whose "composition, which successfully preserves the spirit of the original painting, is outstanding" confirms the school's enduring capacity to unite pictorial invention with metalworking virtuosity.