Pacific 1939-1945: Japan and the Atom Bomb

Was Hiroshima the biggest event of World War 2?

Extracts from an American report on the possible impact of atomic weapons on US cities

Catalogue ref: FO 371/59640

Extracts from report on Hiroshima; FO 371/59640 Extracts from report on Hiroshima; FO 371/59640

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What is this source?

This extract comes from an American report looking at the dropping of the bomb on Hiroshima in 1945. It was very long and detailed and looked at the damage caused to buildings and people. It also looked at the lessons that could be learned from the dropping of the bomb.


This particular extract comments on the possible effects of a Hiroshima type bomb on an American city such as New York.

What’s the background to this source?

The war in the Pacific was fought mostly (but not solely) between US forces and the forces of Japan. It began in December 1941 and cost many thousands of lives. By early 1945 US forces were beginning to invade the islands that made up the Japanese homelands. In February-March 1945 the Allied forces suffered huge casualties when they invaded the tiny island of Iwo Jima. Soon afterwards they suffered heavy casualties again when they invaded Okinawa. After assessing the situation US military and political leaders decided to use the new weapon that they had just developed, the Atom Bomb.


US President Truman consulted his commanders, scientists and also his allies, particularly British leader Winston Churchill. Churchill felt the bomb should be used to shorten the war. The military leaders were divided and many of the scientists who developed the bomb also felt that it was wrong to use it. In the end, Truman did decide to use it, and even said later in his life that the decision was easy.

It’s worth knowing that...

The aim of this section of the report was to analyse how US cities would be affected by atomic attack. This was soon to become a serious threat. Once WW2 ended relations between the USA and the Soviet Union quickly became tense. They intensified in 1949 when the USSR developed its own atom bomb. One key factor that allowed the Soviet Union to develop this technology so quickly was the work of spies who passed on nuclear secrets.


The tensions between the USA and USSR became known as the Cold War.

How will you use this source?

  1. What would you say are the three main points that emerge from this source?
  2. Is it surprising that this report was not made public?
  3. How do you think readers would have reacted to the last sentence of this extract?
  4. Does this source support the view of some commentators that the Hiroshima bomb changed history?
  5. Which parts of the source do you think will be useful in preparing for the TV debate?

Use this table to help you plan your work.