This article employs the theory of buffer zone trade to understand archaeological data related to trade in Wiman Chosŏn (195–108 b.c. ), one of the earliest states in Korean history. Buffer zone trade is performed by an entity (B) placed between a fully developed state with a centralized government (C), and an underdeveloped polity in a periphery (P). B creates a route to convey C’s advanced products, and exports imported goods from C as well as its own products to neighboring polities in the periphery, while controlling the flow of luxury materials. Significantly, in this process B moderates the impact of more powerful and regionally dominant civilizations on the polities in the periphery, therefore preventing these peripheral polities from losing their indigenous cultures entirely or experiencing structural collapse. Furthermore, B exercises authority over the polities in the periphery, controlling the flow of advanced materials. Wiman Chosŏn imported Han’s monetary currency, iron products, weapons, farming tools, high-fired pottery, horse trappings, bronze mirrors, and bronze vessels, while exporting a few simple iron tools like hand knives, bronze mirrors, slender daggers, and fine-lined mirrors to Chin. Interestingly, the discrepancy of both the quality and quantity of the imported Han products takes place in the Korean Peninsula. Additionally, there was no influx of Han currencies and iron weaponry in the southern Korean Peninsula before the second century b.c. I believe that this phenomenon represents a result of trade conducted by Wiman Chosŏn and that Wiman Chosŏn functioned in this way as a semi-core.