'Little Boy' fell on Hiroshima 81 years ago, at 8.15am.
By the end of 1945, around 140,000 people had died in Hiroshima and 74,000 in Nagasaki.
The explosions, which reached temperatures of up to 7,000°C, unleashed a giant fireball, shock waves, and burning fires. Many people died on the spot from the heat, from the fires or beneath collapsing buildings. Others were left with debilitating injuries and permanent damage caused by the radioactive fallout.
Many survivors, known as the hibakusha, went on to develop cancer or other radiation-related illnesses, and were subjected to lasting discrimination. A number of them are still campaigning today for peace and for the abolition of nuclear weapons. The survivors' organisation Nihon Hidankyo was awarded the 2024 Nobel Peace Prize for its efforts.
Shinjiro Koizumi has called for an open debate on a possible nuclear buildup in Japan. Given the military threat posed by neighbouring countries such as China, North Korea, and Russia, the issue, he said, should be discussed "without taboos".
Japan was the only country to have been the target of atomic weapons during the Second World War. Since 1967, it has been bound by the three non-nuclear principles, under which Japan neither possesses, produces nor stations nuclear weapons. Those principles are widely regarded as a symbol of Japanese pacifism.
Experts see military arguments for nuclear deterrence, but caution against the political and diplomatic fallout.
Critics, including atomic bomb survivors, have spoken out strongly against the proposal.
Beyond that, were Japan to acquire its own nuclear weapons, it would have to withdraw from the Nuclear Non-Proliferation Treaty, which is widely seen as an unrealistic move.
