Pearl Harbor Timeline

Year 1941

January: Admiral Yamamoto begins communicating with other Japanese officers about a possible attack on Pearl Harbor.

Jan. 27: Joseph C. Grew, the US ambassador on Japan, wires Washington that he has learned that Japan is planning a surprise attack on Pearl Harbor. No one in Washington believes the information. Most senior American military experts believe the Japanese would attack Manila in the Philippine Islands if war broke out.

February: Admiral Husband E. Kimmel assumes the control of the U.S. Pacific Fleet in Hawaii. US army prepare for the defence of the islands. They ask their seniors in Washington for additional men and equipment to insure a proper defence of military instillations.

April: US intelligence officers continue to obtain Japanese secret messages. Washington does not communicate all the available information to all commands, including Short and Kimmel in Hawaii.

May: A Japanese admiral realized that US was reading his messages. No one in Tokyo believes the code could have been broken, so they did not change the code.

July: Throughout the summer, Admiral Yamamoto trains his air-forces. He also finished the planning about Pearl Harbor.

Sept. 24: The "bomb plot" message from Japanese naval intelligence to Japan's consul general asking for the exact locations of ships in Pearl Harbor is deciphered by US intelligence. The information is not shared with his army at Hawaii.

November: Tokyo sends an experienced diplomat to Washington as a special envoy to assist Ambassador Kichisaburo Nomura, who was trying to seek a diplomatic solution.

Japan wants the U.S. to agree to its southern expansion in Asia diplomatically but if those efforts were unsuccessful, Japan was prepared to go to war.

Nov. 16: Submarines, the first units involved in the attack, depart Japan.

Nov. 26: The main body, aircraft carriers and escorts, begin the transit to Hawaii.

Nov. 27: Hawaii received a message of “war warning" from Washington saying that maybe a Japanese attack is going to happen on an American target in the Pacific.

Night of Dec. 6, Morning of Dec. 7: U.S. intelligence decodes a message pointing to Sunday morning as a date for some type of Japanese action. The message is delivered to the Washington command before 9, more than 4 hours before the attack to Pearl Harbor. But the message is not send on time to the Pearl Harbor commanders and finally arrives when the japanese attack has begun.

In addition to the ships in Pearl Harbor, Japanese army attacked the air stations of Hickam, Wheeler, Ford Island, Kaneohe and Ewa.

The Japanese attack took two hours and 20 minutes. More than 2,400 Americans are dead and 1,200 wounded. Eighteen ships have been lost and 300 aircraft were damaged or destroyed.

Dec. 8: President Roosevelt asked the Congress for a declaration of war against Japan. They agreed and USA declares the war to Japan, entering the Second World War.