After the huge explosion, Ito returned home. His parents survived, but the horror was just beginning.

Ito's 12-year-old brother was severely burned and died a few days later. Ito's 10-year-old sister was at a relative's house when the bomb fell and the house was flattened.

"The survivors left the epicenter of the explosion and headed to the suburbs where our house was. They were badly burned and had difficulty walking. My father invited them to stay at his house, but one by one they breathed their last," recalled Masao Ito, now 82.

In the August heat, bodies needed to be buried but there were no cemeteries. "People moved them to a spacious area, stacked them on top of each other without coffins, poured oil on top to cremate them," he said.

Nearly eight decades later, Mr. Ito rarely talks about the scene, but says the memories remain vivid. “The smell of death was terrible. It’s a scene I really wish I could forget,” he said.

The US atomic bombing of Hiroshima killed 140,000 people in the western Japanese city, bringing World War II to an end.

Mr. Ito's father later died of radiation poisoning. The family business went bankrupt, and he and his mother had to leave Hiroshima to escape debt.

Ito spent a year in the hospital being treated for tuberculosis. When he received a medical aid package from the United States that included medicine and a Bible, he was so angry that he “threw the book against the wall” when he read the line “love your enemies.” “My enemies are the Americans. Why should I love America?” he recalled thinking.

There are few living witnesses like Mr. Ito. After retiring from his banking career, he spent two decades volunteering as a guide at Hiroshima’s peace memorials and museums. He is also an anti-nuclear campaigner.

When he started working as a tour guide, he was disturbed by the words on the memorial: "Let all the souls here rest in peace, for this crime will not be repeated." "I felt I should promise to avenge the dead so they can rest in peace," he said.

But over time, he gradually changed and "began to understand the meaning of the words in the Bible", when he came into contact with Americans devastated by what happened in Hiroshima.

On May 19, G7 leaders will arrive in Hiroshima for a summit. Japanese Prime Minister Fumio Kishida plans to welcome the leaders at the Peace Memorial Park, a memorial to the victims of the atomic bombing, on the opening day.

Mr. Kishida, who is also a member of parliament representing Hiroshima, expressed his hope that his visit to the Peace Memorial Park on the first day of the conference would promote greater awareness of the devastation caused by atomic bombs and contribute to the goal of building "a world without nuclear weapons."

Masao Ito said a world without nuclear weapons seemed impossible, but believed the G7 summit in Hiroshima could send a strong message to world leaders. G7 leaders are also expected to meet with survivors of the 1945 tragedy.

Mr Ito plans to tell G7 leaders about the "temptation of having nuclear weapons". "It would be better not to have them. As long as there are nuclear weapons in the world, the city where you live could end up like Hiroshima".

During his time as a tour guide, the tourist groups that Mr. Ito was in charge of included many students, a group that he said had a "particularly important role."

"I cannot continue to fight forever. Now it is the students' turn to take my place in achieving this goal," he said.

Duc Trung (According to AFP )