In Hiroshima, in early August, the sun is so strong and bright that it fries the sky a shimmering white that hurts your eyes if you stay out too long. This was the baking place where, 67 years ago this week, brilliant American scientists and brave American airmen exploded an atom bomb that seared the sky and instantaneously wiped much of Hiroshima and tens of thousands of people from the face of the earth.
Yet, today, powerful politicians in Japan are hard at work trying to scrap or smash article 9 of the country's constitution - which renounces war - and some of them want to go all out to build a Japanese nuclear weapon.
What are they thinking about? It beggars belief that a country that has suffered so much, first from being - so far - the only victim of nuclear war, and then from bungling over the use of peaceful nuclear energy, should be contemplating building nuclear weapons.
It is almost a game of Chinese roulette. Japan does not know how to cope with the rise of an increasingly assertive and muscular China. It is also obviously concerned about nuclear-armed North Korea.
But Chinese roulette is more suicidal than the Russian version: if Japan built nuclear weapons for first-strike capability against an overbearing China, it would be committing national suicide; second-strike, or retaliatory, capacity might be too late if China had done its job properly. Using nuclear weapons against North Korea, whatever the provocation, seems unthinkable.
That is without considering the suicidal economic costs. France and Britain have discovered that keeping up with the latest nuclear weapons technology is prohibitively expensive. For heavily indebted Japan, it could be the final straw to economic ruin.
Any decision to build nuclear weapons would be a red rag to China, far more serious than the Tokyo government or Japan buying the disputed Senkaku, or Diaoyu, islands. Even so, hawkish Japanese politicians, including Tokyo governor Shintaro Ishihara, claim that flaunting the bomb option will give Japan greater diplomatic clout.
The nuclear option is very much part of shadow politics, going on outside the public arena, but linked to the obvious reluctance to give up nuclear energy. The ability to produce nuclear power gives obvious material and technological advances towards weapons production. Former defence minister Shigeru Ishiba, from the opposition Liberal Democratic Party (LDP), said: 'Having nuclear plants shows to other nations that Japan can make nuclear weapons.'
A group of anti-nuclear experts claims in a book that, 'a group is starting to take a stand to assert the significance of nuclear plants as military technology, a view that had been submerged below the surface until now'. In June, without fanfare, Japan's Diet changed the 1955 Atomic Energy Basic Law to add 'national security' as a reason for using nuclear technology, along with people's health and wealth.
The debate on article 9 has been going on largely behind closed doors. The LDP sees itself as poised to sweep Prime Minister Yoshihiko Noda's government from power. And the party has been busy designing a nationalist campaign that, according to The Economist, 'looks likely to border on emperor-worship'. In April, the LDP published proposals for a constitutional amendment that would eviscerate article 9.
The danger is that Japan's right wing will set the terms of the debate and push a new more militaristic agenda.
The bigger danger, ultimately for Japan itself, is that this small island country seems unable to see itself as the rest of the world does.
As a small example, the main morning news of government broadcaster NHK on Thursday devoted its first 19 minutes to the Olympics, with seven minutes for Japan's judo golds and a minute on Usain Bolt, before celebrating Japan's javelin thrower who failed to qualify for the finals, its decathlon competitor in 26th place and the vital women's field hockey match between Japan and South Africa to decide who comes ninth. There was no mention of the achievements of China, the US, or other parts of the world.
Kevin Rafferty is author of Inside Japan's Powerhouses, an account of Japan Inc and internationalisation