Answer:
The tensions between Japan and the United States were growing for almost a decade. The United States started economic sanctions against Japan. Secondly, when Japan joined the fascist forces in 1940 under Tripartite Pact, it led to direct conflict with the allied countries. The expansionist policy of Japan and its win over Russia and China had boosted the morale of the nation, which was also a major reason to turn its eye towards the Pacific. But the most important reason was the ideology of imperialism and to satisfy that Japan need to control the Pacific and Hawaii was a key to it.
