書経
Yu's flood control work is said to have made him intimately familiar with all regions of what was then Han Chinese territory. According to his "Yu Gong" treatise in the "Book of Documents", Yu divided the Chinese "world" into nine "zhou" or provinces. These were Jizhou (), Yanzhou (), Qingzhou (), Xuzhou (), Yangzhou (), Jingzhou (), Yuzhou (), Liangzhou () and Yongzhou ().