The Japanese launched a surprise attack on American military bases at Pearl Harbor, Hawaii, on December 7, 1941. More than 2,400 people were killed, and many ships and planes were destroyed which President Franklin Roosevelt referred to as a "Day of Infamy."
It was the climax of a decade of rising tension between Japan and the United States.
This surprise attack led to the American Congress declaring war against Japan.
Three days after the attack, Germany and Italy, as Japan's allies, declared war on the United States.
Throughout the 1930s, Japan had been steadily encroaching on China, and the United States had been trying to contain Japan's expansion.
Since America supplied more than half of Japan's iron, steel, and oil, Japan was reluctant to push the United States too far, but it was also intent on getting control of its own sources of raw materials.
On September 27, 1940, Japan joined the Triple Alliance with Italy and Germany and began to expand into northern Indochina.
The United States, placed an embargo on aviation gasoline, scrap metal, steel, and iron in response.
After Japan's seizure of the rest of Indochina in July 1941, President Franklin D. Roosevelt closed the Panama Canal to Japanese shipping and added oil to the embargo list.
In October 1941 Gen. Hideki Tojo, leader of the Japanese pro-war party, became premier.
Negotiations seeking a peaceful settlement went on in Washington, but both sides seem to have decided that war was inevitable.
On November 25, 1941, though continuing the discussions, the Japanese dispatched aircraft carriers eastward toward Hawaii and began massing troops on the Malayan border.
American military leaders, expecting a Japanese attack on Malaya, gave only general warnings to U.S. forces in Pearl Harbor.
Adm. Husband E. Kimmel and Gen. Walter C. Short, in command on Oahu, took few precautions; there was no effective air patrol, and neither ships nor planes were safely dispersed.
Japanese planes attacked Pearl Harbor at 7:55 a.m., December 7; a second wave hit an hour later.
By the time the planes returned to their carriers at 9:45, most of the American planes on Oahu were wrecked; eight battleships, three destroyers, and three cruisers had been put out of action; and two battleships, Oklahoma and Arizona, were utterly destroyed.
A total of 2,323 U.S. servicemen had been killed. The next day President Roosevelt spoke for the American people when, before a joint session of Congress, he proclaimed December 7 a "date which will live in infamy."
With only one dissent, Congress granted Roosevelt's request to recognize the state of war that existed between the United States and Japan.
With that vote, America entered World War II.
There were peace talks occurring up until about November 27, 1941.
At that time, negotiations had come to a halt.
The United States put its troops on alert.
On December 6, 1941, President Roosevelt made an appeal for peace to the Emperor of Japan.
Not until late that day did the U.S. decode thirteen parts of a fourteen part message that presented the possibility of a Japanese attack.
Approximately 9 a.m.(Washington time) on December 7,1941, the last part of the fourteen part message was decoded stating a severance of ties with the United States.
An hour later, a message from Japan was decoded as instructing the Japanese embassy to deliver the fourteen part message at 1 p.m. (Washington time).
The U.S., upon receiving this message sent a commercial telegraph to Pearl Harbor because radio communication had been down.
At 6 a.m.(Hawaiian time) on December 7,1941, the first Japanese attack fleet of 183 planes took off from aircraft carriers 230 miles north of Oahu.
At 7:02 a.m., two Army operators at a radar station on Oahu's north shore picked up Japanese fighters approaching on radar.
They contacted a junior officer who disregarded their sighting, thinking that it was B-17 bombers from the United States west coast.
The first Japanese bomb was dropped at 7:55 a.m. on Wheeler Field, eight miles from Pearl Harbor.
The crews at Pearl Harbor were on the decks of their ships for morning colors and the singing of The Star-Spangled Banner.
Even though the band was interrupted in their song by Japanese planes gunfire, the crews did not move until the last note was sung.
The telegraph from Washington had been too late.
It arrived at headquarters in Oahu around noon (Hawaiian time), four long hours after the first bombs were dropped.
Yamamoto developed the following eight guidelines for the attack:
(1) surprise was crucial
(2) American aircraft carriers there should be the primary targets
(3) U.S. aircraft there must be destroyed to prevent aerial opposition
(4) All Japanese aircraft carriers available should be used
(5) All types of bombing should be used in the attack
(6) A strong fighter element should be included in the attack for air cover for the fleet
(7) Refueling at sea would be necessary
(8) A daylight attack promised best results,
especially in the sunrise hours. Many of Japan's Navy General Staff were in
opposition to Yamamoto's plan, but they continued to prepare for the attack. All
of the necessary training was given to troops, and all of the fighters and
submarines were prepared.
