She was just eight years old, but a lifetime later Ayano Hirashima clearly remembers the first time she was exposed to an atomic bomb. It was Monday August 6, 1945, and she was taking off her shoes when the 13-kiloton uranium weapon nicknamed “Little Boy” exploded 635 yards above the center of Hiroshima, 30 seconds after 8.15am.

“I was about to pick up the indoor slippers to go into school when I saw the flash around me,” she says. “Boom! Suddenly I was covered in rubble. I managed to crawl out, and I got home somehow. My feet were bare and they were bleeding. I saw people in the fields — they might have been dead, although I was a child so I didn’t know.”

Remarkably, given how close they were to the explosion, her parents and siblings had escaped alive and without serious injury. As the extent of the destruction became clear, they made their plans to escape the devastated city to the obvious and sensible place — her mother’s home town of Nagasaki.

The train was beset with delays, which probably saved their lives. They arrived in Nagasaki a day later than intended, 25 hours after the city had been struck by the 25-kiloton plutonium bomb known as “Fat Man”. Unaware of the deadly and invisible radiation fizzing around them, they walked through the center of the destruction and unwittingly became members of a grim and exclusive club — the small number of people to have been exposed to two atomic bombs.

In a century of mass killing, the bombings of Hiroshima and Nagasaki marked the beginning of a new era. The end of humanity was transformed from an imaginative notion into a real and active possibility. A small number of people survived the beginning of the end of the world, not once, but twice. Eighty years later, Ayano Hirashima is one of just two known to remain alive.

One other woman, 94-year old Kinuyo Fukui, lives in the city of Aomori in the far north of Japan. But Ayano, 88, still lives in the same place, in the south of Nagasaki, to which her family trekked through the radioactive wasteland.

Nihon Hidankyo, Japan’s leading organization of atomic-bomb survivors, was awarded the Nobel Peace Prize in 2024 for its advocacy in nuclear disarmament.

Japan’s hibakusha, as victims of the atomic bombings are called in Japanese, have established numerous associations over the years, including the Japan Confederation of A- and H-Bomb Sufferers Organizations, or Nihon Hidankyo, which won last year’s Nobel peace prize for its strenuous campaign for nuclear disarmament. As the 80th anniversary of the bombings approaches, just under 100,000 registered hibakusha remain alive, with an average age of 86.

Research suggests that at least 130 people were exposed to both bombs. This month, for the first time, the “double hibakusha” have been institutionalized with the creation of the Double Atomic Bomb Victims’ Families Association, to preserve the memory of their ordeal and to campaign for a world without nuclear weapons.

It has been founded by Toshiko Yamazaki, the daughter of the most famous double hibakusha, Tsutomu Yamaguchi, who died in 2010 at the age of 93. “Even though atomic bomb survivors are engaged in the peace movement, there is no end to conflicts in the world, and we have come to a time when we need to join hands and appeal for peace,” says Yamazaki, 77.

Tsutomu Yamaguchi, who died in 2010, founded the Double Atomic Bomb Victims’ Families Association, for the few survivors of both Hiroshima and Nagasaki and their families.

The official definition of hibakusha includes people who were in the cities when the bombs fell, anyone who entered the stricken cities in the two weeks afterwards, when the radioactive fallout was at its most deadly, and even those who were in the wombs of exposed mothers. Hirashima fulfills the first criterion for Hiroshima and the second for Nagasaki.

Her memories of the aftermath of the second bombing are more vivid than the first. She remembers getting off the train at the last intact station north of Nagasaki, to see gravely injured and dying survivors gathering in the hope of getting out of the city.

“There was a train, and among the injured were people who had already died,” she says. “There were girls in school uniform and whose hair had been burned off. Some kind of fluid was oozing out of them. I felt bad looking at that. There was a young man who had been so badly burned his whole body was black. The grown-ups were just looking at him — no one knew what to do.”

Unaware of the invisible danger, the family walked through the center of the northern suburb of Nagasaki over which the bomb had fallen, having missed its intended target, the military shipyards and docks to the south. Hirashima remembers dead cows and horses by the side of the road. But on foot, and by boat, they reached the family home.

A street in Nagasaki, following the detonation of the “Fat Man” atomic bomb on August 9, 1945.

Five days later, on August 15, Emperor Hirohito announced the surrender and a new era of hardship began for Hirashima and her family.

She was forced to sell flowers picked from the hills to help her family survive. She dropped out of education, so that her brothers could go to school. In her 20s, she suffered colon and ovarian cancer and thyroid problems that caused her throat to swell up — no doctor ever told her as much, but there seems little doubt that they were caused by a double dose of radiation.

There is no conclusive evidence for it, but people believed that hibakusha would give birth to deformed or disabled children. “People used to say that you mustn’t marry a woman who has been exposed to the bomb,” Hirashima remembers. The man who became her husband was a hibakusha himself, who died of cancer in his 70s. But her three sons and five grandchildren have all grown up healthy.

Adult survivors of the bomb, such as the late Yamaguchi, were often haunted by the horror of what they saw. Most of those still alive now were children at the time and, for Hirashima at least, the imperfectness of her memories is a kind of protection.

“Before the bomb, I had pneumonia and almost died,” she says. “I was on the threshold of life and death, but I recovered and then I lived through two atomic bombs. To have done that and to have lived to this age, I can say that I have happiness — or unhappiness with happiness inside it.”

Richard Lloyd Parry is the Asia editor at The Times of London