Yokoya Somin (横谷宗珉), born in in 10 (1670) under the personal name Tomotsune, was the third-generation master of the Yokoya family, the largest metalworking lineage of the period. His grandfather, the first-generation Yokoya Soko, had studied under the Goto house and served the Tokugawa shogunate as an official metalworker. Somin likewise entered shogunal service and trained in the hereditary iebori manner, but — finding the convention-bound idiom of the Goto house unsatisfying and "influenced as well by the tastes of the time" — he resigned his stipend and entered the independent sphere. There he "exercised his abilities to the fullest, achieved great success, and came to be called the founder of ." He cultivated a close friendship with the Kano-school-trained painter Hanabusa Iccho, from whom he "received guidance regarding designs and pictorial conceptions." He also studied with Kano Tan'yu, deepening his art by working from painters' designs. He used the common name Chojiro (later Jihei), the art name Ton'an, and was first called Sochi before adopting the name Somin after his father's death. He died in Kyoho 18 (1733) at the age of sixty-four.
Somin's manner "may broadly be divided into two principal modes": richly modeled with polychrome metal inlay () in gold, silver, and , and , "a technique he originated." In the former mode, his carving displays "an overwhelming abundance of modeled volume" () with "bold rises and falls in the flesh, producing a forceful and crisply articulated carving manner" that "clearly reveals both Somin's Goto lineage and the thoroughness of his training." In the latter, his chisel work shows "pronounced modulation" and "decisive" strokes, "alternating depth and shallowness at will," with "modulations of speed and emphasis that recall ink painting." His command of grounds in , polished surfaces, and techniques such as , , and yobori was comprehensive. Among his most distinctive inventions are the "Yokoya lions" (shishi) — rendered with such immediacy that "one experiences the illusion that the lion might spring forth from the itself" — and his innovative vertically oriented tatezu compositions for , depicting lions, tigers, horses, and other subjects "from the front or from behind." His employ in'-ne roots, kukuridashi, and chikara-gane, while his demonstrate a mastery of negative space, "unfolding a weighty subject with an unforced expansiveness."
The consistently characterize Somin as an artist of supreme technical authority, describing his work as displaying "the very quintessence of Somin's artistry" and "outstanding technical mastery." His ability to harmonize deliberately contrasting ground treatments and carving methods within a single composition is called "an exceptionally difficult task" in which "Somin's outstanding technique is displayed to its fullest." His chisel handling is praised as "at once delicate and boldly expressive," possessing "a severity and awe-inspiring intensity that other craftsmen could not rival." His influence is described as having "exerted a major influence on later generations of metalworkers" — a phrase that appears in virtually every assessment. Whether working in the high-relief of his Goto heritage or in the freely modulated he pioneered, Somin "opened a new direction through freer, life-sketch-based realism," establishing a tradition that fundamentally reshaped the world of -period sword fittings.
