At the initiative of the United States, from 192 1 to 1922, representatives of the United States, Britain, France, Japan, Italy, the Netherlands, Belgium, Portugal and China held meetings in Washington. 1922 On February 6th, representatives of nine countries signed the Treaty on Principles and Policies Applicable to China Incident. This is the so-called "nine-nation convention". It claims to respect China's sovereignty and independence, territorial and administrative integrity, and abides by the principles of "open door" and "equal opportunity" for all China countries.