126 years ago today, on September 6, 1899 (August 2, 1899 in the lunar calendar), John of the United States proposed a note of "open door" policy towards China. On September 6, 1899, U.S. Secretary of State John Hay instructed U.S. ambassadors to Britain, Russia, Germany, France, Japan, Italy and other countries to submit notes to the governments of the host countries on the "open door" policy towards China, also known as the "John Hay Policy". The main contents are as follows: 1. Countries shall not interfere with other countries' "sphere of influence" or investment undertakings and other interests in leased land in China; 2. The tariff rates of goods, ship tariffs and railway transportation fees within the sphere of influence of each country in China are equal to those of other countries. The United States put forward the open door policy in order to safeguard the privileges of all countries in China, ease the contradiction between great powers competing for China, and make the United States keep the Chinese market free and open to American goods in the competition with other countries based on the principle of equal opportunities and equal interests. Because the theory of "sharing interests" helps to coordinate the contradictions between great powers in China, by March 20, 1900, this policy of the United States received satisfactory answers from all countries.