Inside The Horrifying History Of Japanese War Crimes During World War II

Published April 12, 2023
Updated March 12, 2024

Pearl Harbor: One Of The Most Infamous Japanese War Crimes

Japanese War Crimes At Pearl Harbor

US Navy/Interim Archives/Getty ImagesSmoke billows from American battleships during the Japanese attack on Pearl Harbor.

Perhaps the most notorious of all Japanese war crimes is the December 7, 1941 attack on Pearl Harbor in Hawaii. Then, Japanese planes appeared without warning and bombed much of the U.S. Pacific Fleet. They damaged or destroyed nearly 20 of the United States’ vessels — as well as 300 airplanes — and killed 2,400 American soldiers and civilians.

The attack, which drew the United States into World War II, was a war crime because the Japanese didn’t give any warning in advance.

As PearlHarbor.org notes, the 1907 Hague Convention clearly stated that any attack launched “without previous and explicit warning” was against international law. And the Kellog-Briand Pact of 1928, which both the U.S. and Japan had signed, further stated that an act of war like Pearl Harbor should not be used to resolve “disputes or conflicts of whatever nature or of whatever origin they may be, which may arise among them.”

Pearl Harbor Attack

Time Life Pictures/National Archives/The LIFE Picture Collection/Getty ImagesA sailor runs for cover during the attack on Pearl Harbor.

As it turned out, the Japanese actually had prepared a warning for the U.S. But it wasn’t delivered until after the bombing had taken place. According to the Franklin D. Roosevelt Presidential Library and Museum, this was because of delays in translating and typing up the message. American officials didn’t receive it until well after the attack had started.

After the war ended, the Tokyo War Crimes Trials found that the attack on Pearl Harbor had been illegal, and a number of high-ranking Japanese officials were charged with murder and crimes against peace.


After reading about the horrific Japanese war crimes of World War II, learn about the World War II myths that people need to stop spreading. Then, have a look at the worst U.S. war crimes committed during World War II.

author
Kaleena Fraga
author
A senior staff writer for All That's Interesting since 2021 and co-host of the History Uncovered Podcast, Kaleena Fraga graduated with a dual degree in American History and French Language and Literature from Oberlin College. She previously ran the presidential history blog History First, and has had work published in The Washington Post, Gastro Obscura, and elsewhere. She has published more than 1,200 pieces on topics including history and archaeology. She is based in Brooklyn, New York.
editor
Jaclyn Anglis
editor
Based in Brooklyn, New York, Jaclyn Anglis is the senior managing editor at All That's Interesting, where she has worked since 2019. She holds a Master's degree in journalism from the City University of New York and a dual Bachelor's degree in English writing and history from DePauw University. In a career that spans 11 years, she has also worked with the New York Daily News, Bustle, and Bauer Xcel Media. Her interests include American history, true crime, modern history, and science.
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Fraga, Kaleena. "Inside The Horrifying History Of Japanese War Crimes During World War II." AllThatsInteresting.com, April 12, 2023, https://allthatsinteresting.com/japanese-war-crimes. Accessed August 2, 2025.