Characterization of Morphological Variation in Slender Bronze Daggers from Southern Korea

The slender bronze dagger is a key artifact of bronze assemblage from the Early Iron Age and the Proto-Three Kingdoms in the Korean Peninsula. Previous research on slender bronze daggers has attempted classification and seriation to clarify their origin and transition process. However, the slender bronze dagger has been described as undergoing only gradual changes after its basic form was established, without clear morphological shift. This study approaches the morphological variation of slender bronze daggers from the perspective that it is complexly related to not only spatio-temporal variation but also the temporal accumulation of variation and the processes of production and exchange. As these issues are difficult to resolve with a fixed criteria, this study approaches the problem through the tendencies of variation, geographical distribution and patterns of associated artifacts. Machine Learning's RFE (Recursive Feature Elimination) analysis was used to verify the significance of attributes, and Multidimensional Scaling (MDS) was employed to analyze the distribution of variation. As a result, first, it was confirmed that the significance of attributes varies depending on the spatio-temporal unit. Second, as slender bronze daggers undergo transitions and gradually become standardized, distinct regional spheres are distinguished based on morphological similarity. Finally, the morphological variation of slender bronze daggers was interpreted from the perspective of regional production organizations and their relationships. As the regional-level production systems become increasingly organized, ostentation through multiple burials and differentiation in size gradually disappear. Instead, morphological similarity becomes linked to the intensity of interaction. Accordingly, spatio-temporal changes are also confirmed in the distribution of slender bronze dagger burials, associated artifacts, and the utilization of raw material sources.