The answer is complex and depends on what aspect of the war you're referring to. Japan, though initially confident, ultimately underestimated the US's industrial and military power.
Initial Confidence
- Early Victories: Japan's early successes in the Pacific, including the capture of Hong Kong and Singapore, fueled their confidence. They believed in the superiority of their military doctrine and technology, particularly their naval prowess.
- Underestimating the US: Japan's leadership, however, misjudged the US's resolve and capacity for war. They believed the US would be unwilling to commit to a long, costly conflict in the Pacific.
- "One Hundred Days" Plan: Japan's initial war plan, named the "One Hundred Days Plan," aimed for a quick knockout blow before the US could mobilize fully. This plan was based on the assumption that the US would be unwilling to fight a protracted war.
Reality Sets In
- Pearl Harbor: While the attack on Pearl Harbor was a tactical success, it failed to cripple the US Navy and instead ignited American anger and determination.
- Industrial Power: The US, with its vast industrial capacity, quickly ramped up production of ships, planes, and weapons. This outstripped Japan's ability to keep pace.
- Technological Advancements: The US developed new technologies like radar and sonar, giving them significant advantages at sea and in the air.
