World War II in the Pacific By SonicD Sep 1, 1931 Japan invades Manchuria Jun 19, 1933 Changes for Japan Jan 7, 1936 Changes to Japan Jul 7, 1937 Japan declares war on China Period: Dec 1, 1937 to Feb 16, 1938 Japan invades Nanking Dec 12, 1937 Panay Incident Sep 22, 1940 Tripartite Pact Jul 1, 1941 Japan seizes French Indochina Nov 26, 1941 Attack fleet leaves Japan Dec 7, 1941 Pearl Harbor Attacked Dec 8, 1941 US & Britain declare war on Japan