Pearl Harbor

By paigekressley

  • Japan invades North China from Manchuria

  • Trade Sanctions

    U.S. imposes trade sanctions, followed by an embargo, aimed at curbing Japan's military aggression in Asia.

  • Possible attack on Pearl Harbor

    Adm. Yamamoto begins communicating with other Japanese officers about a possible attack on Pearl Harbor.

  • Fleet

    Adm. Husband E. Kimmel assumes command of the U.S. Pacific Fleet in Hawaii. Kimmel and Lt. Gen.Walter C. Short, commanding general of the Hawaiian Department, prepare for the defense of the islands

  • Monitor Japan

    U.S. intelligence officers continue to monitor Japanese secret messages. In a program code-named Magic, U.S. intelligence uses a machine to decode Japan's diplomatic dispatches. Washington does not communicate all the available information to all commands, including Short and Kimmel in Hawaii.

  • Codes

    Japanese Adm. Nomura informs his superiors that he has learned Americans were reading his message traffic. No one in Tokyo believes the code could have been broken. The code is not changed.

  • Finalizing plans

    Throughout the summer, Adm. Yamamoto trains his forces and finalizes the planning of the attack on Pearl Harbor.

  • Tokyo sends an diplomat

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

  • Learning of possible attack

    Joseph C. Grew, the U.S. ambassador to Japan, wires Washington that he has learned that Japan is planning a surprise attack on Pearl Harbor

  • "Bomb plot"

    The "bomb plot" message from Japanese naval intelligence to Japan's consul general in Honolulu requesting a grid of exact locations of ships in Pearl Harbor is deciphered. The information is not shared with the Hawaii's Adm. Kimmel and Gen. Short.

  • Submarines, the first units involved in the attack, depart Japan.

  • The main body, aircraft carriers and escorts, begin the transit to Hawaii.

  • "War warning"

    Kimmel and Short receive a so-called "war warning" from Washington indicating a Japanese attack, possibly on an American target in the Pacific, is likely.
  • Period: to

    U.S. decodes a message

    U.S. intelligence decodes a message pointing to Sunday morning as a deadline for some kind of Japanese action. The message is delivered to the Washington high command before 9 a.m. Washington time, more than 4 hours before the attack on Pearl Harbor. But the message is not forwarded to the Pearl Harbor commanders and finally arrives only after the attack has begun

  • Pres. Roosevelt

    President Roosevelt addresses Congress and asks for a declaration of war against Japan, which he receives