The Japanese believed that the solution to their economic problems was to use military force to gain control of lands that were rich in resources. Through a series of military conquests, they gained economic and political control over territories that were rich in natural resources. Following the outbreak of World War I in 1914, the Empire of Japan declared war on the German Empire and quickly seized the possessions of the German colonial empire in the Pacific Ocean (the Northern Mariana Islands, the Caroline Islands and the Marshall Islands) with virtually no resistance.
