Cities as Administrative Units and the Development of Urban Systems in the Song, Liao, Jin and Yuan Dynasties

China witnessed an urban revolution during the Song, Liao, Jin and Yuan dynasties, expressed in the shift from the fangshi pattern (which separated fang [residential areas] from shi [marketplaces]) to the xiangfang pattern (under which cities were divided into several districts [xiang] and sub-districts [fang] and business and residential areas were mixed). Urban space went from being closed to opening up. With regard to administrative institutions, individual cities appeared in the Song Dynasty as administrative units, a development marked by the establishment of the duxiang, a specialized administrative government department. Growth in the number of such cities in the Liao, Jin and Yuan dynasties was marked by the establishment of a variety of administrative departments at different levels. On this basis, a closely linked system of cities set out in an orderly manner took shape in the Jin and Yuan dynasties.