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The attack of December 7, 1941 is one of the best-studied events of the 20th century. Yet there are many Pearl Harbor facts that remain largely unknown. Below is listed seven Pearl Harbor facts that you likely didn’t know.

The White House decoded a Japanese war declaration the day before Pearl Harbor

Japan sent a message to its embassy on December 6th to inform diplomats to prepare for a declaration of war. The White House intercepted the message and decoded it, but FDR did not warn his command at Pearl Harbor.


Since 1897, America had a plan to impede Japanese power

First conceived as early as 1897, America’s contingency plan for the rise of Japan as a modern military power was named War Plan Orange. The plan was updated on a regular basis to reflect the size of US and Japanese fleets.

The Pacific Fleet moved to Pearl Harbor for protection

Admiral Richardson moved his Pacific Fleet to Pearl Harbor because he believed that the shallow water would protect ships from aerial torpedo attacks.

FDR’s Chief of Naval operations told him not to believe rumors of a Japanese attack

Rumors about a Japanese attack on Pearl Harbor circulated for months. FDR was warned on several occasions, even by the British Navy, about the vulnerability of Pearl Harbor. He chose, instead, to listen to his chief of Naval operations and ignore the threat.

An American Newspaper helped provoke the Japanese

On October 31st, United States News (the predecessor of U.S. News and World Report), printed a spread that showed how easy it would be for United States B-17 bombers to blow Japan off the map.

FDR made Admiral Kimmel the scapegoat

Admiral Kimmel, who had taken charge of Pearl Harbor, repeatedly warned FDR of a possible attack. FDR did not share the decoded Japanese threat with Kimmel, but instead eventually demoted him.

Japan Almost Seized Hawaii

Admiral Chuichi Nagumo failed to launch a third wave to destroy oil tanks and dry docks; if Japan launched the third wave, they would have captured the islands. The US began to issue currency stamped “HAWAII” to servicemen in Oahu so the Japanese could not spend it elsewhere in case they did capture the islands.


This article on Pearl Harbor facts is part of our larger selection of posts about the Pearl Harbor attack. To learn more, click here for our comprehensive guide to Pearl Harbor.

This article is from the book Operation Snow: How a Soviet Mole in FDR’s White House Triggered Pearl Harbor © 2012 by John Koster. To uncover more of the secrets, spies, and shockers that surrounded the events of Pearl Harbor, buy a copy of Operation Snow. You can visit its sales page at Amazon or Barnes & Noble.

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"Pearl Harbor Facts: 7 Things You Never Knew About the Attack" History on the Net
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February 21, 2024 <https://www.historyonthenet.com/pearl-harbor-facts>
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