Literature Reference: 金函开诏拜夷王。—— 《送源中丞赴新罗》 The golden casket opens the imperial edict to bestow the title upon the foreign king. Source from 'Song Yuan Zhongcheng Fu Xinluo'.
金: Gold, the precious metal. Symbolizes the prosperity of wealth and abundance.
函: The term refers to a letter and its envelope.
Meaning: Golden casket symbolizes nobility and authority, containing important edicts, representing a mission and honor.