門戸開放政策
In finance, American efforts to preserve the Open Door Policy led in 1909 to the formation of an international banking consortium through which all Chinese railroad loans agreed in 1917 to another exchange of notes between the United States and Japan. There were renewed assurances that the Open Door Policy would be respected, but the United States would recognize Japan's special interests in China (the Lansing–Ishii Agreement). The Open Door Policy had been further weakened by a series of secret treaties in 1917 between Japan and the Allied Triple Entente that promised Japan the German possessions in China after the successful conclusion of World War I. The subsequent realization of the promise in the 1919 Versailles Treaty angered the Chinese public and sparked the protest known as the May Fourth Movement. The Nine-Power Treaty, signed in 1922, expressly reaffirmed the Open Door Policy.