This study examines the classification of rice cultivars presented by Seo Yu-gu in Gongmyeonggo 穀名攷 (Treatise on the Names of Grains) to analyze the specific utility he pursued while composing this commentary. This utility manifests in three primary dimensions: first, the adoption of taxonomic categories and the system-atic identification of diverse rice varieties aimed at mitigating the potential risks inherent in the transplanting method in wet-rice cultivation and addressing the mi-cro-ecological sensitivity of the method under the climatic conditions of the Kore-an Peninsula; second, the integration of empirical field knowledge regarding Jo-seon cultivars, accompanied by vernacular terms to eliminate ambiguity in matching nomenclature with physical objects, thereby converting the tacit knowledge of local veteran farmers into a communicable medium accessible to rural elites; and third, a comprehensive survey of Chinese rice varieties paired with logical arguments supporting the feasibility of their cultivation in Joseon, which was anticipated not only to increase agricultural productivity but also to prepare for unprecedented climate disasters incorporating an analysis of his other treatise, Ohaego 五害攷 (Treatise on the Five Disasters). Ultimately, this research contrib-utes to the broader historiography of late Joseon myeongmulhak 名物學 (The study of names and things) by demonstrating that the field was driven by the pur-suit of practical utility, rather than an inquiry into external objects for its own sake as seen in modern natural history.