Answer: Vasco de Gama's arrival in India of 1498.
Explanation: The event that opened Asian nations, particularly China, to trade with Europe was Vasco de Gama's arrival in Calicut, India, in 1498.
Before this period, Middle Eastern traders controlled the trade routes between China and European countries. These traders charged very expensive prices, which limited imports and exports to and from China. When Vasco de Gama discovered an alternate trade route leading into Asia, many European powers were influenced to trade with China and Asian nations more. From the 16th - 19th centuries, a trading post in Macau was established which maximized trades between the Chinese and Asian nations (particularly the British).