In September 1940, during World War II, the newly created regime of Vichy France granted Japan's demands for military access to Tonkin with the invasion of French Indochina (or Vietnam Expedition). This allowed Japan better access to China in the Second Sino-Japanese War against the forces of Chiang Kai-shek, but it was also part of Japan's strategy for dominion over the Greater East Asia Co-Prosperity Sphere. On 9 March 1945, with France liberated, Germany in retreat, and the United States ascendant in the Pacific, Japan decided to take complete control of Indochina. The Japanese launched the Second French Indochina Campaign. The Japanese kept power in Indochina until the news of their government's surrender came through in August.