How was the first nuclear weapon

Background current

On August 6 and 9, 1945, the United States dropped two atomic bombs on the Japanese cities of Hiroshima and Nagasaki. To this day, people suffer from the consequences of the use of nuclear weapons.

To this day, the ruins of a former exhibition hall in Hiroshima are a reminder of the dropping of the "Little Boy" atomic bomb as a peace memorial. (& copy picture-alliance, Zoonar / Marco Brivio)

Japan's rise to a regional great power

At the beginning of the 20th century, parts of East and Southeast Asia were occupied by European colonial powers. Japan was able to maintain its independence and rose to a regional great power after the victory in the Russo-Japanese War in the years 1904/05. Japan soon established a protectorate in Korea, which was annexed as a colony by the Japanese Empire in 1910. In 1926, Hirohito ascended the Japanese imperial throne. Nationalist forces increasingly gained influence.

In November 1936, Japan signed the "Anti-Comintern Pact" with the German Reich. In it the two states agreed to fight the "Communist Internationals" (Comintern), and other states joined in the following years. At the end of 1937 the Second Sino-Japanese War began, as a result of which Japan occupied large areas in eastern China. The soldiers often used brutal force: in the Nanking massacre, which began on December 13, 1937, according to various estimates, between 40,000 and 200,000 civilians were murdered. Japan claimed supremacy in Asia. In the "Greater Asian Prosperity Zone" the remaining colonial powers were to be driven out and the countries under Japanese leadership were to be forcibly united.

Japanese attack on Pearl Harbor

The attack on the US naval base at Pearl Harbor in Hawaii on December 7, 1941, which led to the USA entering into World War II, is considered to be the turning point in the Japanese aspiration to become a great power. In the following years, the Japanese sphere of influence in the Pacific was pushed back. In March and June 1945, the defensive positions Iwojima and Okinawa, which were already part of the Japanese national territory, fell. However, there was no telling that the empire would capitulate.

On July 16, 1945, during the Potsdam Conference, the United States successfully completed the test of the world's first nuclear weapon explosion - the "Trinity" bomb. On July 24, US President Harry S. Truman ordered the atomic bomb to be used over Japan, depending on the weather over one of the cities of Hiroshima, Kokura, Niigata or Nagasaki. On the same day Truman is said to have informed the Soviet leader Josef Stalin about the existence of a "new weapon of special destructive strength" at the Potsdam conference. According to reports from the Soviet delegation, Stalin already knew about the successful test of an American atomic bomb and ordered the development of a Soviet atomic bomb to be stepped up. This point in time is therefore also considered to be the beginning of the nuclear arms race.

Attacks on Hiroshima and Nagasaki

The city of Hiroshima was the first target of the US armed forces. The city was also of strategic importance because of its industrial and military facilities. The bomb, code-named "Little Boy", was dropped on August 6, 1945 at 8:15 am local time. According to various reports, between 90,000 and 120,000 people were killed immediately or succumbed to their injuries in the following months in the city, which had an estimated 300,000 inhabitants. About 90 percent of the houses were destroyed or badly damaged.

A war correspondent walks through the rubble of Hiroshima city several weeks after the atomic bomb was dropped. (& copy picture-alliance / AP)

Since the Japanese government did not unconditionally surrender even after the bombing on Hiroshima, the US government decided to drop a second bomb. Initially, the port city of Kokura was planned as the site of operation. Due to the heavy cloud cover, Nagasaki, a little more than 100 kilometers away, was approached. Between 60,000 and 80,000 people died in Nagasaki.

The casualty figures for both bombs are still controversial today. Not all human remains were found in the bomb detonation center, and many records of who lived in the city were destroyed in the process. In addition, tens of thousands died as a result of the attack in the months and years that followed.

On August 15, Japanese Emperor Hirohito made a radio address to the public, saying that Japan must now "endure the inevitable" and end the struggle. The unconditional surrender was signed on September 2nd on board the US battleship Missouri and is considered the end of World War II.

Numerous long-term cancer cases

Hundreds of thousands of survivors of the two atomic bombs in 1945 had to struggle with serious consequences. These include diseases that were triggered directly by radiation or burns, but also long-term effects - such as cancer and deformities in children. In Japan the survivors are called "Hibakusha". If they are recognized as victims, they are entitled to free medical treatment.

In the first ten years, the number of leukemia cases increased among the Hibakusha. Later, there was an increased incidence of thyroid, breast, lung and bladder cancer. The US-Japanese "Radiation Effects Research Foundation" is investigating whether radiation has an impact on future generations. So far, the research institute has not found any solid evidence for this.

Memory in Hiroshima

The culture of remembrance of the atomic bomb attack is also reflected in the reconstruction of Hiroshima. The "atomic bomb dome" - a former exhibition building made of brick with a striking dome, which was one of the few in the city center to survive the bombing, at least in its basic structure - was left as a memorial for August 6, 1945. In addition, a so-called "Peace Boulevard" was laid out. In many other Japanese cities today, however, there is little reminiscent of the Second World War.

Since 1947 the "peace bell" has been rung in Hiroshima on August 6th at 8:15 am. The dead from back then will be remembered in a ceremony. The current mayor calls for the abolition of nuclear weapons and calls for peace in the world. In its 1946 constitution, Japan pledged never to wage war again. In addition, the country passed the "non-nuclear principles" in 1967, according to which it rejects the possession and importation of nuclear weapons. However, in the course of the nuclear armament in North Korea, there were repeated debates as to whether these principles should be reconsidered.

International bombing debate

In the United States, shortly after the two atomic bombs were dropped, a heated debate about the use of nuclear weapons began. The then supreme commander of the US armed forces in Europe, General Dwight D. Eisenhower, is said to have been against the operation. After the beginning of the Cold War, the USA and Japan became closer again. To this day, numerous US soldiers are stationed in bases on Japanese territory, and Japan is also protected by the US nuclear shield. In 2016, Barack Obama was the first US president to take part in the memorial service in Hiroshima. However, he did not apologize for the bombing.

A 2015 study by the Pew Research Center showed that at that time only 56 percent of Americans were of the opinion that the atomic bomb attack of 1945 was justified. The proportion of those who agreed to the dropping for unspecified reasons also fell from 85 percent in 1945 to 57 percent in 2005.

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