Understand the Manchu conquest and its impact on European trade.
Manchu had a very reactive military (entire empire was militarized) so when the Ming had internal problems, series of weak rulers, corrupt gov, ineffective administrations due to ineffective emperors, Manchus we able to conquest when the Ming was falling. The Manchus came from the North in Manchuria. European trade connections that the Ming had made were continued in the Manchu, China's economy prospered and expanded until the Opium War. However, China banned foreign trade in all places but in the port of Canton during the trading season of October-March. The Canton System helped the Chinese control foreign trade especially since they did not want much from the Europeans, but silk, tea, and porcelain was wanted from the Chinese.