The Qing government decreed a prohibition of non-Eight Banner people getting into Northeast China. Han Chinese were banned from settling in this region but the rule was openly violated and Han Chinese became a majority in urban areas by the early 19th century.[1]
Spence, Jonathan D. (2002), "The K'ang-hsi Reign", in Peterson, Willard J. (ed.), Cambridge History of China, Vol. 9, Part 1: The Ch'ing Dynasty to 1800, Cambridge: Cambridge University Press, pp. 120–182, ISBN 0521243343.