Pearl Harbor Day: Timeline of key events leading to the Japanese attack

NEW YORK - This Saturday marks the 83rd anniversary of Pearl Harbor, as the nation honors the victims and survivors of the Dec. 7, 1941, attack.

The Events Leading to the Attack on Pearl Harbor

The Japanese attack on Pearl Harbor on Dec. 7, 1941, killed 2,400 Americans and injured 1,200 more. It stands as one of the deadliest assaults on U.S. soil.

"Since the War of 1812, no foreign power had carried out so devastating an attack on American soil, and virtually all Americans reacted to this one with shock, disbelief, and outrage," wrote historian Gary Gerstle from the University of Maryland.

The capsized USS Oklahoma and the USS Maryland, two of the ships destroyed in the attack on Pearl Harbor. (Photo by © CORBIS/Corbis via Getty Images)

On this anniversary, let’s revisit the key events that led up to that fateful day:

1937

July: Under Prime Minister Fumimaro Kanoe, Japan invades North China.

1940

July: The U.S. imposes trade sanctions and an oil embargo to counter Japan’s military expansion. This cripples Japan’s oil imports by 90%, threatening its long-term war efforts.

September: The U.S. cracks Japan's diplomatic code, allowing it to decode secret messages.

The U.S.S. California is hit during the Japanese attack on Pearl Harbor. (U.S. Navy via Library of Congress)

1941

January: Japanese military leaders begin planning an attack on Pearl Harbor.

Jan. 27: U.S. ambassador to Japan, Joseph C. Grew, warns Washington of a potential surprise attack on Pearl Harbor. However, U.S. officials believe an attack would occur in Asia.

November:

• Japan sends Ambassador Kichisaburo Nomura to Washington to negotiate a diplomatic solution.
• Nov. 16: Japanese submarines leave for Pearl Harbor to prepare for an attack.
• Nov. 26: Diplomatic talks fail, prompting Japan to deploy aircraft carriers and warships toward Hawaii.
• Nov. 27: President Roosevelt issues a Pacific war warning, but it goes largely unheeded in Hawaii.

Dec. 6: U.S. intelligence decodes a Japanese message pointing to imminent action, but the information isn’t relayed to Honolulu commanders in time.

Captured Japanese photograph of the bombing of Pearl Harbor army base. Dec. 7, 1941.

Dec. 7, 1941

7:02 a.m.: U.S. radar operators detect incoming aircraft near Oahu but assume they are B-17 bombers from California. No alarm is raised.

7:55 a.m.: Japanese warplanes launch a surprise assault on Pearl Harbor, targeting naval ships and airfields at Hickam, Wheeler, Ford Island, Kaneohe, and Ewa Field. The attack lasts two hours and 20 minutes.

When it ends, 18 U.S. ships and over 300 aircraft are destroyed or damaged. More than 2,400 Americans lose their lives, with 1,200 more injured.

Dec. 8, 1941

President Roosevelt delivers his famous address to Congress, calling December 7 "a date which will live in infamy." Congress swiftly declares war on Japan, marking the U.S.'s entry into World War II.

This devastating attack forever changed the course of history, cementing Pearl Harbor’s place as a pivotal moment in American and global affairs.