Towards war with the USA
Japan separated Manchuria from China in 1932 and invaded parts of China, occupying
Peking and Shanghai. After the defeat by Soviet troops on the border of Manchuko in 1939 Japan
The formation of a pro-Japanese government in Nanking in 1940 and the invasion of Indo-China led to a conflict with Brit./American interests. The Allies were unable to prevent the blocking of the Burma road. Chiang Kai-chek's China was isolated and the sources of raw materials in Malaya and Indonesia were threathened.
The USA reacted to Japanese expansion by imposing quarantine and cancelling the 1911 trade agreement. An embargo on oil and scrap metals weakened Japan's armament industry and Japanese accounts were blocked by the USA, Britain and the Dutch East Indies. Japanese-American negotiations, in which the USA called for withdrawal from China and Indo-China, failed.
Japan's reaction was the attack on Pearl Harbour in order to paralyse the American Pacific fleet which led to the a declaration of war by the USA and Britain. Germany and Italy in turn declared war on the USA.