1940 March 30 Wang Jingwei forms a pro-Japanese government in Japanese-occupied Nanjing.
May 7 Pearl Harbor is made the main base for the U.S. Pacific Fleet.
June 4 The United States embargoes exports of industrial equipment to Japan.
June 14 German forces begin to invade Paris, leading to the fall of France.
July 22 Konoe becomes prime minister for the second time; Matsuoka Yosuke becomes foreign minister.
From late July to early August U.S. exports of metals, aviation gasoline, and lubricating oil to Japan come under strict federal control.
August 1 Matsuoka uses the term “Greater East Asia Coprosperity Sphere” to sum up the government’s ambition to build a self-sufficient regional bloc under Japan’s leadership.
September 23–29 Japan occupies the northern half of French Indochina.
September 25 The United States increases its financial assistance to Chiang Kai-shek.
September 26 The United States embargoes the sale of steel and scrap iron to Japan, to go into effect on October 16.
September 27 Japan signs the Tripartite Pact with Germany and Italy.
October 12 The Imperial Rule Assistance Association is formed under Konoe’s presidency, putting an end to Japan’s party politics and beginning the New Order Movement.
October 31 Dance halls are closed and jazz performances become illegal in Japan.
November 10 The twenty-six-hundred-year reign of the Japanese imperial house is celebrated nationwide.
1941 January 8 Army Minister Tojo Hideki issues “Instructions for the Battlefield,” commanding soldiers to die a soldier’s death rather than become captives; this code, glorifying heroic death, will form the basis of Japan’s wartime credo.
February 11 The Japanese ambassador to the United States, Nomura Kichisaburo, arrives in Washington, D.C.
March 12 Matsuoka leaves for his grand tour of Europe to meet Japan’s Axis partners, Hitler and Mussolini.