Goryeo missions to Imperial China
Goryeo missions to Imperial China were the diplomatic ventures of Kingdom of Goryeo which were intermittently sent in the years 918–1392, representing a significant aspect of the international relations of mutual Goryeon-Chinese contacts and communication. A cautious diplomacy was the foreign policy of the Kingdom of Goryeo up through its demise in 1392.
Source: Wikipedia — Goryeo missions to Imperial China (CC BY-SA 4.0)