Prevailing models of social development for the southern Korean Iron Age (ca. 300 b.c.–a.d. 300) focus on contact with China as well as the dynamic interaction between local polities to explain the development of socio-political complexity but the nature of this contact has not been critically examined or its more granular processes explored. This article uses two prominent grave good types discovered in southeastern Korean burials to question these models as well as conceptions of archaeological cultures in the region more generally. These objects, Chinese bronze mirrors and iron objects decorated with bracken-like spiral designs, both indicate significant interaction with Han China via its administrative commanderies, but their production and diverse mortuary contexts do not conform to any current model of culture contact, acculturation, hybridity, or entanglement. The variable production processes, expression of exotic motifs through these objects, and the way these objects were interred in graves suggests that we should look for cultural unity and early indicators of socio-cultural complexity within regions where local groups were particularly active in expressing their differences within a set of agreed-upon parameters. I argue that the southern peninsula is best described as a set of interdependent local groups with a similar ritual vocabulary, but little to no political unity even directly prior to the appearance of the Three Kingdoms polities of Paekche, Silla, and Kaya.