The Atomic Bomb Dome, as it is known today, is seen at dusk in Hiroshima, western Japan. Photo / AP
The crowd sat entranced as 78-year-old Emiko Okada recalled the horrifying events of August 6, 1945, a day that started hot and cloudless. There was the buzz of the plane, the huge flash, the cries for water, the kids like ghosts with skin dangling off them, the people with their guts hanging out.
"We don't want you young generations to go through what I did. You can help by spreading what you just heard from me to other people," Okada - a hibakusha, or "atomic bombed person" - said this week not far from the spot in Hiroshima where American forces dropped Little Boy, the first atomic bomb to be used in warfare, 70 years ago yesterday.
Not only is Okada telling her own story, but she is training an apprentice to continue telling her tale after she's gone: a memory keeper, one of a growing number here being designated as an "A-bomb legacy successor" as survivor numbers dwindle.
While there are still more than 183,000 survivors of Hiroshima or Nagasaki alive in Japan today, their average age now is 80.
Okada's designated storyteller is a 39-year-old man who works in a Tokyo department store and has no direct ties to Hiroshima. But since visiting the city as a student, Yasukazu Narahara has become almost as ardent as Okada when it comes to making sure people do not forget the bombing.
Japanese children do not dwell for long on World War II at school, with curriculum guidelines saying that students should understand the war "caused sufferings to all humanity at large". A recent poll by public broadcaster NHK found only 30 per cent of adults could correctly date the Hiroshima attack, and even fewer the Nagasaki blast.
"I hope I can build a relationship with her like a son" so Okada will bequeath him her innermost thoughts, Narahara said after the session where she spoke.
Bells tolled in Hiroshima on Thursday. Tomorrow the Nagasaki attack will be commemorated.
Prime Minister Shinzo Abe and foreign dignitaries were among the tens of thousands gathered in Hiroshima's Peace Memorial Park to observe a moment of silence at 8.15am local time, when the detonation turned the western Japanese city into an inferno.
No one knows exactly how many people died in the blast, but the Manhattan Engineer District says there were at least 105,000 deaths. Other estimates exceed 200,000. Imperial Japan surrendered days later, although there were people on both sides - including US General Dwight Eisenhower - who believed Japan was looking for a way to admit defeat even before the bombings.
Abe is taking tangible steps towards removing some of the shackles imposed on Japan by its American occupiers 70 years ago.
He wants to reinterpret the pacifist constitution to enable Japan's "self-defence forces" to take a more active military role, including by coming to the United States' defence. The proposal has sparked virulent protests at home, with many Japanese saying their war-renouncing constitution has served them well over the past seven decades.
Okada is strongly dismissive of Abe's plans and is worried lessons are not being learned.
"Of course, I hope that students will be taught about this at school. I want young people to learn why the atomic bombs were dropped," she said after her talk. "We need to talk about what Japan did to other countries, too."
Another survivor has the same fears. "I'm part of the last generation who can tell the story of these events in living form," said Okihiro Terao, who was 4 that day.
Like Okada, Terao does not directly criticise American actions that day - at least, not openly. But both strongly oppose Abe's plans to move Japan back to a military footing. "It makes me want to cry," Terao said. "Something terrible like this could happen again. It's no joke. We've been a peaceful country for this long, why do we need to go backwards in history to how it used to be 70 years ago?"
Terao weathered the August heat outside the dome this week, while the surprisingly energetic Okada tells her story to school groups and other visitors. But Narahara has taken on the responsibility of telling her story at other events, speaking also further afield, particularly in Tokyo.
Narahara, who was already volunteering at Hiroshima's Peace Memorial Museum, went through the training programme being run by Hiroshima's city government to produce the next generation of atomic bomb storytellers. Currently, 210 people with an average age of 55 are learning to recount testimonies at the museum and nearby memorial.
"The biggest challenge is how to tell a story about someone's experience in someone else's words," said Ayami Shibata, who leads the three-year programme.
Okada said it's important to tell her story in her own voice. "Can successors pass on the words that come out of our souls, something so painful?"
One child certainly learned the lesson this week. Chizuko Hyodo, who lives near Tokyo, brought her 9-year-old, Haruka, to the session. After listening to Okada, Haruka simply said: "It was really scary."
Witnesses to the event which forever changed the world
Seven decades ago, the United States dropped an atomic bomb on the Japanese city of Hiroshima. It almost instantly levelled most of the city and killed as many as 140,000 people. Three days later, on August 9, another American bomber dropped a nuclear device on the city of Nagasaki, killing 40,000 to 80,000 people.
The devastation was followed by World War II's swift conclusion. It's seared into the collective global memory - no other time in history has a nuclear weapon been used in war. But what of the victims? Here are some of the eyewitness testimonies.
He was on his way to school. At a train station, he saw a "dazzling flash of light, brighter than even the sun", and then "an ear-splitting roar", followed by a seismic explosion that shattered glass everywhere.
"My forehead felt hot, and I unconsciously touched it with my hand," Taketa said. "When I looked at the sky over Hiroshima, I saw a tiny, glittering, white object, about the size of a grain of rice, tinged with yellow, and red, which soon grew into a monstrous fireball. It was travelling in my direction, and I felt as though it was going to envelop me."
Akiko Takakura
The then 20-year-old was near the hypocentre, or "ground zero" of the bomb. "What I felt at that moment was that Hiroshima was entirely covered with only three colours. I remember red, black and brown ... nothing else. Many people on the street were killed almost instantly. The fingertips of those dead bodies caught fire and the fire gradually spread over their entire bodies from their fingers. A light grey liquid dripped down their hands, scorching their fingers."
Those who found shelter after the explosion entered a strange, hideous world, where everyone's hair was literally fried and human shadows were etched on to stone.
"I felt the city of Hiroshima had disappeared all of a sudden," said the 14-year-old in line for school. "Then I looked at myself and found my clothes had turned into rags due to the heat. I was probably burned at the back of the head, on my back, on both arms and both legs. My skin was peeling and hanging like this."
Michiko Hachiya
Hachiya was then the director of a hospital in Hiroshima. "There were the shadowy forms of people, some of whom looked like walking ghosts. Others moved as though in pain, like scarecrows, their arms held out from their bodies with forearms and hands dangling. These people puzzled me until I suddenly realised that they had been burned and were holding their arms out to prevent the painful friction of raw surfaces rubbing together."