The school arose in Province, a region celebrated for iron production since antiquity. The early eleventh-century miscellany Sarugaku-ki already lists "the swords of " among the noted products of the provinces, and roughly two centuries later the swordsmiths emerged as heirs to that high reputation, flourishing chiefly in the lower basin of the Takahashi River in such locales as Koji and Manju. The school is traditionally said to have begun with Yasutsugu around the Shoan era, and thereafter it prospered greatly down to the later part of the period. Within this lineage, works produced up through approximately the mid- period are distinguished as , while those from the late period onward through the era are broadly termed . Representative smiths of the phase include Tsugunao, Tsuguyoshi, Moritsugu, and Naotsugu, yet a great many surviving blades are and attributed to the school collectively rather than to individual hands, reflecting the depth and continuity of the tradition as a whole.
The identifies two principal modes of workmanship. The first is a -based temper in which the tends toward tightness, producing a bright and clear effect; the second is the distinctive - that reached full maturity around the Enbun era (1356-1361), during the height of the period. works are generally , with a somewhat (subdued) in mixed with small undulations; by the late period the becomes calmer, and in pieces the tightens and the construction shifts to . It is specifically noted that whereas smiths of other provinces in this period display under the influence of the tradition, works remain -- a hallmark distinction. The forging characteristically shows mixed with , with finely standing grain producing the so-called (crepe-like texture); (patchy, mottled surface features) and (sooty-toned areas) are frequently intermingled. The regularly exhibits , and toward the cutting edge a layered, streak-like known as is a major highlight of the school. Fine adheres thickly, with entering well. Overall, when compared with works of the era, blades present a somewhat restrained and austere taste.
Across the tradition's long arc from the late period to the close of the era, the consistently praises works for the brightness and clarity of both and , frequently employing the term (clear, brilliant) to describe the . Blades are commended for being (sound and well-preserved), for retaining ample (blade "flesh"), and for conveying an atmosphere of sincerity and quiet elegance. The recurring evaluative language -- "the salient points of are conspicuously displayed," "an especially fine example even among works attributed to this school" -- underscores the 's regard for the tradition as one producing consistently high-caliber work whose collective identity is immediately recognizable. The school's -period output, with its wide , imposing , and bold that rises and returns with a pointed tendency, conveys the powerful period character of that age, while earlier pieces are valued for their thoroughly archaic feeling and deep flavor. Taken together, the school represents one of the major traditions of western Japan, distinguished by its refined forging, luminous , and the singular visual drama of its effects.