The Yanagawa (柳川) school ranks among the principal ("town carving") lineages of metalwork, arising in the mid- period as a direct offshoot of the Yokoya house. Its founder, Yanagawa Naomasa (1692–1757), studied under Yoshioka Inaba-no- and under Yokoya Sōmin, and established himself in the Otamagaike district of . The consistently locate the school within this filiation, styling it "the Yanagawa branch within the Yokoya lineage" (横谷門下柳川派) and naming Naomasa as the family founder (家祖). Naomasa had no biological heirs and devoted himself to the training of disciples, and the successive heads of the house inherited the character nao (直). The middle generations passed through Naomitsu, the second master: Naoharu, the biological son of Naoyuki and the eldest grandson in the direct line of the founder Naomasa, lost his father suddenly shortly after his birth and "therefore trained under the support and guidance of Naomitsu." When Naomitsu retired in the Kansei era, Naoharu succeeded to the headship as the third-generation master, and, in the words of the , "went on to produce notable artists such as his own son Naotsura and Kōno Haruaki, thereby enlivening the world of -period metal carving."
The collective idiom of the school is the classic Yokoya-derived vocabulary of kinkō work: grounds of (赤銅) dressed in (魚子地), high-relief carving () — frequently executed as applied motifs () — and polychrome inlay (zōgan iroe) in gold, silver, and , deployed across , , , , and . The school was likewise renowned for excellent (single-cut carving), and its repertoire favored classical subjects: shishi (lions) with peonies, tigers, Chinese sages, and figural themes such as the Seven Lucky Gods. Fidelity to the manner of Sōmin remained the school's touchstone across generations. Naoharu's of Fukurokuju, inscribed "After Sōmin's design", draws this praise in its : "The high-relief carving, with its pronounced depth and height differences, together with the inlaid , is truly splendid, achieving a level that closely approaches Sōmin himself," the inlay and colored-metal decoration being "applied with precise placement." Equally characteristic is the school's mode of transmission, whereby pupils composed their art-names from characters granted by the Yanagawa masters.
The measure of the Yanagawa school's significance lies as much in what it engendered as in its own production. Ishiguro Masatsune, a pupil of Katō Naotsune of the Yanagawa school, formed his name by combining masa (政) from Naomasa and tsune (常) from Naotsune; the record that he "moved beyond the manner of the Yanagawa school, devising innovative treatments particularly within bird-and-flower subjects," founding the Ishiguro lineage, which "continued to prosper through successive generations until the Meiji period" and produced the celebrated "twin peaks" Masayoshi and Masaaki. Kikuoka Mitsuyuki (born 'en 3, 1750), who studied under Yanagawa Naomitsu, became the founder of the Kikuoka school and "is highly regarded for precise and solid carving technique." Naoharu's pupil Kōno Haruaki opened yet another current, transmitted in turn to pupils such as Ōishi Akichika, whose Kaei-era work "clearly carries forward the style of his teacher Haruaki." Through these ramifying lines, the Yanagawa school served as the essential conduit by which the Yokoya manner of on grounds was disseminated across the late- metalworking world.