Michiko's 15-year-old face was destroyed in an instant. Even today, after more than two dozen operations and under heavy make-up, it looks mottled and lumpy, as if reconstructed from burnt clay. She rarely looks at interviewers directly.
As she flew through the air from the force of the blast, Michiko knew she'd been bombed. "I thought, goodbye Mother." It was her mother who helped pull her from the wreckage, her face swollen like a balloon, skin hanging from her arms in ribbons.
"I lost all my hair. My face was so awful I hid for a long time. If I had been alone I probably would have killed myself but my mother was there every day taking care of me, even though she was sick herself. I stayed alive for her." Her mother died in 1979. When they cremated her body they found shards of glass in the ashes, so deeply had they been embedded from the force of the bomb.
Like many of the 270,000 hibakusha or survivors of the bombings of Hiroshima and Nagasaki, Ms Yamaoka lives with constant pain. She has fought breast cancer and thinning bones and grimaces when she moves around her tiny apartment. "My body hurts, but it is more painful to remember what I saw that day, although I feel I have to." By the end of 6 August, 160,000 people were killed or injured; many more died afterwards from the effects of the bomb. Every year the city adds names to the list of victims, which today officially stands at 237,062.
In Nagasaki, bombed two days after Hiroshima, 74,000 people died within less than a year as the city became, in the famous words of its mayor, a place of death "where not even the sound of insects could be heard".
Survivors have been haunted by illness. Hitoshi Takayama developed cancer in his back and hip. Much of the muscle from his back was removed, he says, asking me to touch it. It feels bony and cold. "I don't mind showing people my injuries if it teaches them about what happened."
Suzuko Numata was 20 and days from marriage in Hiroshima when a collapsed building shattered her left leg. Three days later her leg was amputated below the knee, without anaesthetic. "We used to chant during the war: Be united in one mind like a fireball, 100 million people," she recalls. "Then when the bomb fell the trucks came around and ignored women and children, and just helped the healthy men. We were no use to them. That's when I first understood what war really was." She later learnt that her fiancé had been killed.
Like many women injured in the blast, she has never married, a victim of what they call "hibakusha discrimination".Men suffered too. "Nobody wanted to marry someone who might die in a couple of years," says Sunao Tsuboi, who was burnt from head to toe in the aftermath of the Hiroshima bomb. "We were watched very closely to see if we would die." Later he fell in love with a girl whose parents refused to give them permission to marry. "We decided to commit suicide together and took pills but we didn't take enough. When we woke up and cried together, we were so happy to be alive."
Once a major military hub, Hiroshima is today an airy, tree-lined city of a million people that nurses its wounds very publicly, with museums, memorial parks and peace boulevards. Some accuse the Japanese of emphasising their own pain while their schools, history books and popular culture play down the suffering they inflicted on others.
Official Hiroshima defends itself against these claims. "We don't intend to play up our victimhood," says Minoru Hataguchi, director of the Hiroshima Peace Memorial Museum. "We make efforts here to show what Japan did to other Asian countries."
Ordinary hibakusha take the criticisms personally. "I know what we did to others," says Ms Yamaoka. "I've been to Hawaii, Korea, China, Okinawa and the US and seen what we did, so now I can say what I like. I criticise all governments. I tell children to come to Hiroshima and see what war means."
In March, Paul Tibbets, the pilot of Enola Gay, the plane that dropped the "Little Boy" atomic bomb on Hiroshima, was asked again whether he had any regrets. He replied: "Hell no, no second thoughts."
But a mea culpa of sorts came in May from Robert McNamara, the former US defence secretary, who as an air force officer helped plan the fire bombings of 57 Japanese cities.
In an essay for Foreign Policy magazine he called the nuclear legacy of Hiroshima "so bizarre as to be beyond belief". And, wrote the man who came within a "hair's breadth" of sparking nuclear annihilation during the Cuban missile crisis of 1962: "I have never been more fearful of a nuclear detonation than now."Reuse content