On August 6, 1945 the US dropped an atomic bomb (“Little Boy”) on Hiroshima in Japan. Three days later a second atomic bomb (“Fat Man”) was dropped on the city of Nagasaki. These were the only times nuclear weapons have been used in war.

Reasons for the bombing

Many reasons are given as to why the US administration decided to drop the atomic bomb on Hiroshima and Nagasaki. Reasons include the following:

• The United States wanted to force Japan's surrender as quickly as possible to minimize American casualties.
• The United States needed to use the atomic bomb before the Soviet Union entered the war against Japan to establish US dominance after the war against Japan and to secure Japanese surrender to the US.
• The United States wanted to use the world's first atomic bomb for an actual attack and observe its effect.

Given all of these reasons, the US was in quite a hurry to drop the bomb. Shortly after successfully testing history's first atomic explosion at Trinity, New Mexico, on July 16, 1945, the order to drop the atomic bomb on Japan was issued on July 25.

The impact of the bombing on Hiroshima

Hiroshima stands on a flat river delta, with few hills to protect sections of the city. The bomb was dropped on the city centre, an area crowded with wooden residential structures and places of business. These factors meant that the death toll and destruction in Hiroshima was particularly high.

The firestorm in Hiroshima ultimately destroyed 13 square kilometres (5 square miles) of the city. Almost 63% of the buildings in Hiroshima were completely destroyed after the bombing and nearly 92% of the structures in the city had been either destroyed or damaged by blast and fire.

Estimates of total deaths in Hiroshima have generally ranged between 100,000 and 180,000, out of a population of 350,000.

The impact of the bombing on Nagasaki

Due to the hilly geography of Nagasaki and the bombing focus being away from the city centre, the excessive damage from the bombing was limited to the Urakami Valley and part of downtown Nagasaki. The centre of Nagasaki, the harbour, and the historic district were shielded from the blast by the hills around the Urakami River.

The nuclear bombing did nevertheless prove devastating, with approximately 22.7% of Nagasaki's buildings being consumed by flames, but the death toll and destruction was less than in Hiroshima. Estimates of casualties from Nagasaki have generally ranged between 50,000 and 100,000.

The fact that the Nagasaki bomb was more powerful and also the narrowing effect of the surrounding hills did mean that physical destruction in the Urakami Valley was even greater than in Hiroshima. Virtually nothing was left standing.

The city of Hiroshima invites people from around the world to participate in making paper cranes to remember those who died in Hiroshima and Nagasaki. This action started in memory of Sadako who was two years old when the atomic bomb was dropped on Hiroshima and later died of leukaemia caused by the exposure to nuclear radiation. Believing that folding paper cranes would help her recover, she kept folding them until she passed away on October 25th, 1955, after an eight-month struggle with the disease.

Sadako's death inspired a campaign to build a monument to pray for world peace. The Children's Peace Monument was built with funds donated from all over Japan. Now, approximately 10 million cranes are offered each year before the Children's Peace Monument.

Anyone may place paper cranes before the Children's Peace Monument in Peace Memorial Park. If you can't go to the park yourself you can send cranes to the following address:

Peace Promotion Division
The City of Hiroshima
1-5 Nakajima-cho Naka-ku
Hiroshima 730-0811 JAPAN

You are asked to include your name, the name of your organization (if you are participating as a school or any other group), your address (or the address of the organization), your E-mail address, the number of cranes, and any message you wish to submit. This way your information can be submitted to the Paper Crane database and your desire for peace will be recorded.

For instructions on how to fold paper cranes visit one of the following sites:
http://www.sadako.org/foldingcranes.htm
http://www.hiroshima-is.ac.jp/Hiroshima/foldcrai.htm
http://rosella.apana.org.au/~mlb/cranes/startup.htm

For more information click on the following links:
http://www.nuclearfiles.org/redocuments/unit4.html
http://www.pcf.city.hiroshima.jp/peacesite/English/Stage1/S1-3E.html

Definition of a nuclear bomb – explanation of how nuclear bombs work http://people.howstuffworks.com/nuclear-bomb1.htm

Information on the Manhattan Project and the circumstances in which the bombs were used
www.needham.k12.ma.us/high_school/cur/Baker_00/03/baker-es-mk-03-/manhattan.htm

Truman’s decision to drop the bombs
www.trumanlibrary.org/whistlestop/study_collections/bomb/large/bomb.htm

Historical documents on the decision to drop the bombs
www.dannen.com/decision/

Hiroshima Peace Site
www.pcf.city.hiroshima.jp

Photos and descriptions of the city after the bombing
www.exploratorium.edu/nagasaki/

The Sadako Peace Project
www.sadako.org

Nuclear Files is a project of the Nuclear Age Peace Foundation which provides a history and analysis of the Nuclear Age
www.nuclearfiles.org

The Bulletin of the Atomic Scientists is a publication of the Educational Foundation for Nuclear Science (EFNS) focusing on “global security issues, especially the continuing dangers posed by nuclear and other weapons of mass destruction, and about the appropriate roles of nuclear technology”.
www.thebulletin.org

National Atomic Museum in America
www.atomicmuseum.com