Yu Gong
Before Qin unified China, each state had its own customs and culture. According to the "Yu Gong" or "Tribute of Yu", composed in the 4th or 5th century BC and included in the "Book of Documents", there were nine distinct cultural regions of China, which are described in detail in this book. The work focuses on the travels of the titular sage, Yu the Great, throughout each of the regions. Other texts, predominantly military, also discussed these cultural variations.