Following the surprise strikes that Japan carried out against the British Empire on December 7, 1941 in Hong Kong, Singapore, and Malaya, Britain and Canada were the first countries to declare war on Japan before the United States did so in retaliation. These assaults were a part of a bigger strategy to damage the warships of the United Kingdom and the United States in the Pacific in order to seize control of Southeast Asian countries. Both the British and the American navy suffered significant losses as a result of the attacks, indicating that the operation was mostly successful.
In addition, the Japanese were successful in seizing control of a substantial section of Southeast Asia, which they would maintain for the subsequent three years.