ABSTRACT
The Yangtze Valley grew in importance as a productive centre during the Eastern Tsin, and the other southern dynasties definitely assuming the position of the Key Economic Area from the time of the T’ang dynasty. Politically, the centre of gravity still lay in the north. The constant menace of nomadic invasion on the northern frontier emphasized the strategic importance of the northern provinces. Tradition and political inertia undoubtedly also contributed to the decision to keep the political capital in the north, from the Sui to the Ch’ing dynasties, despite the shifting of the Key Economic Area to the south. Large-scale public works, like the construction of the Grand Canal, require a mass-mobilization of labour. The attraction of the Yangtze valley as the centre of gravity, economically as well as politically, was also expressed in the growing importance of the city of Nanking, the chief city of the region.
