was inevitable that some kind of military showdown between Imperial Japan and the United States would have to take place. As Japanese armed forces were much smaller than those of the United States, the only chance the Japanese had against the Americans was by using the element of surprise. And that’s precisely what was used in the attack on Pearl Harbor, which was successful precisely because the Americans were totally unprepared for what was coming.

While the significance of the date would only happen later, Japan attacked Pearl Harbor early on a Sunday morning because they knew that it would add to their element of surprise. They knew that the army base would still be sleeping at that early time, and most people would have the day off. By picking a day with good weather, the Japanese bombers could hit as many battleships as possible, though they missed the major target on the island: the fuel reserves. The Japanese fleet also missed the aircraft carriers that were out on maneuvers at the time. If these had been hit, it would have been harder for the United States to recover.

The attack on Pearl Harbor also fit into a larger strategy. Within days, Japan attacked the Philippines and the Aleutian Islands. The combined attack on the Pacific fleet with an ambitious campaign of aggression was meant to demonstrate Japanese strength and intimidate the United States. In reality, it only galvanized American opinion against the Axis. Japan's attack on Pearl Harbor was so unexpected that Japanese diplomats were still present in Washington that morning trying to work out a deal to get munitions. When notified of the attack, Secretary of State Cordell Hull accused the diplomats of a breach of honor even though they were not aware of the exact timing of the attack. Even though the attack on Pearl Harbor claimed over two thousand lives, it did not destroy the American fleet; actually, it was a provocation on an entire country that would fight the Axis until their unconditional surrender in 1945.

The Japanese attacked Pearl Harbor on December 7, 1941, a Sunday, for several reasons. First, the Japanese had been expanding their empire for several years, including into China in 1937. They had signed a pact with the other Axis powers (Germany under Hitler and Italy under Mussolini), and they had taken over French Indochina in 1941. In reaction, the United States froze Japanese assets and embargoed petroleum and other products going to Japan. Hence, the Japanese wanted to retaliate against the United States. Second, the Japanese wanted the U.S. out of its way as it pursued further expansion in the Pacific.

The Japanese chose December 7 for the Pearl Harbor attack partly because it was a Sunday--a day when many of the troops would be resting or attending religious services. The first dive bomber arrived at Pearl Harbor just before 8 am, and the battleships in the harbor were open targets because the American planes were grounded at that time. A private in the U.S. Army had noticed the Japanese aircraft on his radar system, but he was told that the planes were American, as the Americans were expecting the arrival of planes. The early morning raid was also conducted on a clear day, so the weather helped the Japanese in their aims. In the attack, more than 2,300 Americans were killed, and the Pacific fleet took a large hit, as several battleships were sunk and 180 aircraft were destroyed. On December 8, 1941, the U.S. declared war on Japan, and President Franklin D. Roosevelt called the attack "a day which will live in infamy."