It is a subdivision of what is traditionally called Korea's Three Kingdoms period and covers the first three centuries of the Common Era, corresponding to the later phase of the Korean Iron Age.

When Gojoseon was defeated by the Han dynasty of China in 108 BC,[1] the northern region of the peninsula and Manchuria was occupied by the states of Buyeo, Goguryeo, Okjeo, Dongye, and other minor statelets.

Important features of this period include the widespread production of iron artifacts for daily use and the introduction of grey earthenware pottery with a beaten pattern.

The introduction of iron technology enabled the manufacture and use of stronger and sharper weapons and agricultural tools, resulting in an acceleration of political integration, as well as greater concentrations of power and wealth.

Contact with the cultures of the lower basin of the Nakdong River is demonstrated by archaeological evidence from China, Wae, and Manchuria.