Someya Tomonobu was the son of the Ise province metalworker Someya Masachika. It is transmitted that he studied painting under the Edo bunjin painter Tani Buncho (1763--1841), who established the literati-painting tradition in the Kanto region, and indeed his manner is one that readily persuades the viewer of the truth of this tradition. Through innovations of his own devising, he established a distinctive approach to landscape carving (sansui-bori), earning favorable reputation and recognition, and he is regarded as a craftsman with a strongly personal idiom. By incorporating the Chinese-style landscape themes favored by the literati painters of his day into the medium of the sword guard, he opened up a new direction in tsuba design.

Tomonobu's art lies in the translation of nanga-style ink landscape painting into chokin (metal carving). Making full use of broad chisels, fine chisels, and specialized chisels in masterful combination, he gives form to a world uniquely his own. His sukidashi-bori is characteristically restrained in height, and his meticulous chisel work on mountain and rock surfaces evokes the stippling (tenbyo) brush manner of literati painting. In works employing colored metals, his palette remains subdued -- gold, silver, and irogane are arranged to recall the light, dilute coloration encountered in literati painting rather than to dazzle. Where iron alone is the medium, foreground elements are executed in crisp, sharply defined relief while distant mountains and clouds transition to gentler, more relaxed chisel work, producing an effect akin to viewing a monochrome ink landscape. This distinctive ground-roughening chisel work applied to mountain surfaces is especially characteristic of Tomonobu.

Tomonobu's expressive methods are careful and precise, yet they convey no sense of contrivance; instead, a natural ambience is rendered with a quiet, austere (kotan) tone. The NBTHK consistently appraises his finest works as pieces in which a pictorial landscape is "successfully translated into the medium of the tsuba," achieving a level where one views the guard as though contemplating a hanging scroll of nanga painting. His ability to evoke billowing clouds through subtle variations in the flat ground, and to suggest trailing mist and the very sounds of the mountains through chisel technique alone, places him among the most distinctive individualists of late-Edo tosogu metalwork -- an artist who, through the study of painting, opened an independent artistic realm within the craft.