China was nearly isolated from the rest of the world. Foreign trade was strictly controlled. Foreigners were only allowed at a port in Guangzhou.
The British forced China to open five ports to British trade in 1842. A couple of years later, the United States received extensive privileges for trading.
America wanted to trade with China like European countries and others. These countries had a sphere of influence . This was a geographic area where an outside nation exerts special economic or political control.
Secretary of State John Hay proposes the Open Door Policy in 1899. The goal of this policy was to provide all nations equal trading rights in China. Hay sent notes to other countries such as Great Britain, Germany, Russia, Japan, France and Italy.
Anti Foreigner sentiments grew as more countries were vying for businesses in China. The society of Righteous and Harmonious Fists (Boxers ) attacked foreign missionaries and Chinese Christians. This caused the Boxer Rebellion in June of 1900.
Americans help to stop the Boxer Rebellion. This helps to increase China's trust in the United States. The Open Door Policy gained support. Western nations then realized that competition among themselves would hurt their ability to exploit China Trade.