Kuniyasu (國泰), also read Kunitai, is traditionally held to have been a son of Taro Kunimura, the founder of the school of Province. Kunimura himself is regarded as the maternal grandson of Kuniyuki of Yamashiro, and from this lineage many capable smiths emerged -- Kuniyoshi, Kunitoki, Kunitomo, Kunisuke, Kuninobu, Kunitsuna, and others. The school flourished in the Kumafu area of Kikuchi District from the closing years of the period through the period. Among extant dated works by Kuniyasu, examples bearing dates from the Enkyo, Gentoku, Shokei, and Kenmu eras are known, placing his active career squarely in the late to early transition. The name was succeeded by later generations, and a second-generation Kuniyasu working in the mid to late period can also be identified.
The workmanship of the school generally resembles that of the Yamashiro tradition, and individual differences among the group's smiths are not strongly pronounced. Nevertheless, certain distinguishing features are consistently noted: a conspicuous tendency toward in the forging; steel that tends to appear somewhat whitish, with standing out; a showing a degree of character, with calmer activity within the ; and a with slightly fuller rounding at the tip, often tempered with a comparatively shallow return. Within this shared framework, however, Kuniyasu's individuality is clearly perceived. The repeatedly identifies him as the smith within the school whose work shows the strongest tendency toward dense . His blades characteristically display thickly adhering in both and , with and running through the temper, and and effects that at times produce a -like aspect. When the forging is especially fine, both ground and edge achieve a brightness and clarity reminiscent of Kunimitsu. His forms, though often encountered as , retain deep curvature, while his display the characteristically thick and of the late idiom. Signed works are comparatively few; in the signature, the right-hand interior portion of the -gamae radical is carved into a distinctive ear-like shape, a characteristic shared among school signatures that cannot readily be confused with other smiths.
The 's evaluative language for Kuniyasu is notably consistent across sessions spanning five decades. His finest works are described as specimens in which "both and are bright and clear" and the forging "stands out as distinctly superior." He is recognized as one of the leading figures of the lineage, and his work is rated jo-jo (superior-superior) in the Fujishiro ranking. The recurring observation that his strong character imparts an "individual and somewhat unconventional character" within the otherwise homogeneous school positions him as the smith whose personality most clearly transcends the group's collective manner. At his best, the interplay of thickly laid , dense , and a bright yields a result that the acknowledges as recalling the workmanship of the main line -- a fitting testament to the school's ancestral ties to Yamashiro.