The US-Japan War Talks as seen in official documents

The Washington Conference (January 1921 to February 1922), proposed by the United States and attended by Japan, Great Britain, the United States, Italy, and France, was an international conference that focused on naval arms control and issues in the Far East and Pacific regions, attempting to establish international order following World War I. At the conference, the United States proposed the prohibition of ship building for ten years as well as a limit to the quantity of capital ships possessed by the Unite States, Great Britain, and Japan to the ratio of 5:5:3. Considering Japan’s financial burden and cooperation with the Unites States, the Japanese plenipotentiary, Tomozaburo Kato, agreed to the treaty in principle. He then proposed the prohibition of establishing new or improving existing naval bases and fortresses on Pacific Islands and received approval. The Anglo-Japanese Alliance was abrogated, and in its place, the Four-Power Treaty (signed by Japan, Great Britain, the United States, and France), which sought to maintain the status quo in the Pacific, was agreed to. In regards to China, the Nine-Power Treaty (signed by the United States, Great Britain, France, Japan, Italy, Belgium, the Netherlands, Portugal, and China), which affirmed the sovereignty, territorial and administrative integrity, as well as prohibited exclusive rights to the country as per the Open Door Policy, was established. The system of international order comprising the broad range of treaties and regulations was termed "the Washington System."

Following the Washington Conference, successive cabinets up to the early Showa Period, with exception to the Giichi Tanaka Cabinet that sent troops to Shandong, followed a policy of cooperation with the United States by complying with the Washington System. With the exception of the Tanaka Cabinet, Kijuro Shidehara, who represented Japan at the Washington Conference, was in charge of Japanese diplomacy for five years and three months as Foreign Minister in the Takaaki Kato Cabinet, from June 1924 until leaving his job during the general resignation of the second Reijiro Wakatsuki Cabinet in December 1931. The basic approached of Shidehara foreign policy was that friendly ties with China and cooperation with the United States and Great Britain went hand in hand with adherence to the Versailles Treaty, the peace treaty ending World War I, as well as various treaties from the Washington Conference.

However, triggered by the Liutiao Lake Incident in September 1931, Japan expanded the strategic range of the Kwantung Army from the Manchurian Railway area to the entire South Manchuria area (the Manchurian Incident). This was an open challenge to the Washington System. U.S. President Hoover replied with criticisms of Japan’s morals instead of economic sanctions on Japan as a way to war. U.S. Secretary of State Stimson trusted Minister of Foreign Affairs Shidehara in the beginning and adopted non-intervention / wait-and-see policy. However, after the bombing of Jinzhou by the Kwantung Army in October, Stimson stiffened his attitude toward Japan and proposed a disapproval policy. In January 1932, Stimson declared that he would never approve a challenge to the Nine-Power Treaty / the Pact of Paris as an Instrument of National Policy by using armed forces, and he issued a notice denying the political change in East Asia caused by the Manchurian Incident (the Stimson Doctrine). Furthermore in a form of publicly-released letter to U.S Foreign Relations Committee Chairman Boller, Stimson reaffirmed the significance of the Washington System and announced the warning that the U.S. would be released from the restriction of Article 19 (defense restrictions related to the Philippines and Guam) of the Five-Power Treaty, because of the Japanese violation of the Nine-Power Treaty. Japan approved Manchuria as a country in September of the same year and gave notice of withdrawal from the League of Nations in March 1933, the following year. This caused a breakdown in international coordination of the Washington System in East Asia. Japanese diplomatic isolation and souring of the Japan–U.S. relationship became significant because of the expanded Sino–Japanese War in July 1937. Japan ended up refusing to participate in the Nine Power Conference held in Brussels in November 1937. At this point, the Washington System had completely collapsed.