1. Japanese expansionism and militarism: In the early 20th century, Japan was a rapidly growing and industrializing nation with ambitions to expand its empire. The Japanese military, in particular, was strongly influenced by a philosophy of militarism and believed that Japan's destiny lay in conquering and dominating East Asia.
2. Economic pressure: Japan was also facing severe economic pressure in the 1930s, due in part to the global economic crisis and the Western powers' embargo on oil and other resources. This pressure increased the urgency for Japan to secure access to natural resources in the Asia-Pacific region, including the Dutch East Indies (present-day Indonesia) and the Philippines.
3. The rise of the United States as a Pacific power: The United States had emerged as a major Pacific power by the early 20th century, and its growing presence and influence in the region was seen as a threat by Japan. The United States had also imposed economic sanctions on Japan in response to its aggression in China, further straining relations between the two countries.
4. The attack on Pearl Harbor: The Japanese attack on Pearl Harbor on December 7, 1941, was the culmination of months of planning and preparation. The attack was intended to cripple the U.S. Pacific Fleet, thereby removing a major obstacle to Japanese expansion in the Pacific.
The attack on Pearl Harbor was a major turning point in World War II, bringing the United States into the conflict and ultimately leading to Japan's defeat.