Large-scale 2nd to 3rd century AD bloomery iron smelting in Korea

Iron production in Korea has traditionally been seen in the shadow of developments in cast iron technology in China, with limited indication for a northern influence via Russia’s Maritime Province. The possibility of the existence of bloomery iron production in ancient Korea has been little explored, and relevant discussion is fraught with speculations based primarily on the early use of cast iron. The recent excavation of a site in South Korea recovered substantial amounts of slag providing direct evidence of bloomery smelting. The accelerator mass spectrometric dating of burnt wood from inside one of the slag pieces showed that the site was in use in the early 3rd century AD or earlier, which is in agreement with the assessment based on ceramic typology. The traits of a bloomery process evident in the slags’ microstructure, shape, composition and excavation context are discussed along with the implications for historical iron technology in Korea, where cast iron and the influence from China have been overly emphasised.

► Slag from a Korean iron site was examined for microstructure and composition. ► Radiocarbon age by AMS placed the date in the early 3rd century AD or earlier. ► Evidence of an established bloomery smelting technology was found. ► Contact with the north is proposed as a probable source of early Korean iron. ► Questions are raised to the theory of Korean iron originating purely from China.