This chapter explains how the imperial urban system expanded into south China. After the fall of the Han Dynasty, fighting in the north caused southern migration, particularly after the An Lushan Rebellion in 755. This led to the growth of commercial cities in the Lower Yangzi Delta, which were linked to the northern capitals via the Grand Canal after the reunification of China under the Sui Dynasty. At the same time, Chinese cities were linked to the medieval international world over land along the Silk Road, and over sea via Guangzhou. In northern capitals, which reflected the influence of the Kaogongji, cities continued to be walled and divided into wards. However, in the Lower Yangzi Delta commercial cities were more open plan. Meanwhile, the arrival of Buddhism and Daoism into China brought monasteries and temples into cities, while monks began to take responsibility for aspects of urban governance along with imperial officials. Wards divided cities socially as well as physically. The wealthy enjoyed lavish lifestyles, built palaces and mansions, donated to monasteries, and constructed gardens. Goods and people from outside China made cities more cosmopolitan, and writers reflected on this and other aspects of urban life in their poetry.

During the Tang-Song transition, urbanization created regionally distinct hierarchical networks of large and small cities, market towns, and villages, which were closely connected in complex economic, social, and political relationships. The Lower Yangzi Delta was the most urbanized region of China, and remained linked to northern capitals via the Grand Canal. Within Chinese capitals, emperors, aristocrats, and officials remained enclosed within palace and imperial cities. Outside, the ward system broke down, and in many smaller cities there were no walls at all. Now commerce could be found along every street, and it also brought new forms of social organization and governance. Merchants organized different trades into guilds and took their place alongside the state and religious institutions in governing urban life. In capital cities, imperial families continued to assert their symbolic right to rule through participation in now well-established rituals. Elsewhere, people from all social classes were more invested in the urban life of their city, and distinct urban cultures emerged. Local gentry wrote urban histories and guides, bought and sold property, and invested in businesses or religious institutions. They describe lives of urban men and women in levels of detail that do not exist for earlier eras.