Yi is what that communicates the Dao of heaven and that of human" recoded in Guodian Chu Jian·Yu Chong (a compilation of manuscripts copied on the bamboo slips of the state of Chu, one of the Warring states, excavated at Guodian, Hubei Province, China) might be the earliest and most explicit proposition now available to express the thought of unity of heaven and human.

Review of Practical English Conversation for WTO;