TOKYO—The US atomic bombings that flattened Hiroshima and Nagasaki 60 years ago "castrated" the Japanese, giving birth to a meek, geek culture that has nearly tamed their warrior impulse, top Japanese pop artist Takashi Murakami says.

In every nerdish animation, the pony-tailed Murakami sees images of mushroom-cloud explosions evoking the world's only nuclear attacks.

"I wondered why and thought something like the trauma of the atomic bombings may have taken deep root in us," Murakami told AFP as he unveiled his latest sculpture at the trendy Roppongi Hills shopping and residential complex.

"Since the days we were little, images of Japan's defeat in World War II, especially with the force of atomic bombs, have fallen all over us in books, cartoons and television programs," he said.

"We, the Japanese people of middle age or younger, have ever since lived in a castrated world where people give no heed to such thoughts as the prosperity of the country or national identity," said the 43-year-old artist.

"It's my hypothesis but I think this gave birth to the otaku," he said.

"Otaku" -- which translates loosely as "stay-at-home" describes the Japanese hobbyists who verge on the fanatic about attractions such as comics, video games and computers.

And the same trauma that led to the otaku has driven the Japanese to avoid friction with others at any cost.

"Japanese people have adopted a principle of don't-rock-the-boat and aren't good at acknowledging one another through personality clashes," said Murakami, sporting round-frame glasses and a bearded chin.

Murakami said that as a Japanese, his feelings are naturally "negative" about the August 1945 atomic bombings that killed more than 210,000 people in Hiroshima and Nagasaki.

But the artist who has collaborated with Louis Vuitton also believes the bombings have brought some cultural changes.

"The Japanese used to expand the country's territory by massacring other peoples to build the so-called 'Greater East Asia Coprosperity Sphere'," he said, referring to Japan's aggression in much of the region.

The "Pokemon" pocket monsters and the "Mushi King" battling bugs are examples of how the Japanese spirit to fight cannot be suppressed completely, he said.

Murakami is on a brief return to Japan after organizing a pop art exhibition in New York named "Little Boy", the codename of the bomb that levelled Hiroshima.

His latest work, the fourth edition of Mr Pointy and the Four Guards, is a seven-meter (23-foot) tall sculpture built on a Buddhist motif. The onion head statue stands in a pond with lotus flowers at Roppongi Hills.

The artist is perhaps best known for his life-size "Miss KoKo" an improbably busty life-size figure in an ultra-short waitress outfit which sold for 567,500 dollars at Christies in New York in 2003.

Nuclear references have crept up in Japanese culture ever since the attacks. The iconic Godzilla monster in the original 1954 film rose out of a roiling sea and swam to Japan after being awakened by a hydrogen bomb test.

But the Japanese response, in Murakami's view, is characteristically mild.

In a foreign country, someone like cartoonist Yoshinori Kobayashi, whose nationalist books have sold more than a million copies, would cause a social movement demanding a higher global profile for Japan, Murakami says.

"In Japan, however, people read his books, saying 'That's right! I respect him,' and that's it," he said.

Could the Japanese unite and change back to the ways of the past?

"The answer is 'No' because we are happy now, because we know we would suffer if we unite," he said.

"I grew up in a very poor area, and one of my goals in life was to get out of poverty. But I hardly see such kids nowadays," he said.

As for the future Japanese heroes, Murakami predicts more people will come to love peaceful characters such as Doraemon, a cartoon cat-like robot also known as Ding-dong elsewhere in Asia.

An easy-going friend and savior, Doraemon helps the pathetic boy Nobita, who is doing poorly at both school and sports, by producing miraculous futuristic gadgets from a "four-dimensional" pouch on his belly.

Some people are critical of the robot, saying it helps children too easily. But Murakami argued that the character is set to conquer the world.