Our grandfathers stood above and below both mushroom clouds. Our friendship proves reconciliation is possible.

Ari Beser (left) and Kosuzu Harada

Eighty years ago, the best physicists on the planet came together and unlocked the fundamental forces of the universe—not to heal or create, but because they believed doing so would end a war that had already killed tens of millions. In doing so, the United States unleashed a weapon so destructive it reshaped the world in its image.

Two planes. Two bombs. Two hundred thousand lives extinguished almost instantly. A light so hot it seared bodies where they stood, burned neighborhoods to ash, and left behind ghostly silhouettes—negatives of human existence. Peace, the Americans believed, had been won. But peace through bombs proved a paradox. The very weapons that helped end one war birthed a terror we have yet to escape.

The lucky died instantly. The unlucky survived through hellfire so horrible that even photographers present could barely bring themselves to click the shutter. Kosuzu’s grandfather Tsutomu Yamaguchi was among the unluckiest, for he was one of the only people who survived both atomic bombings, first of Hiroshima and then of Nagasaki three days later.

On August 6, 1945, while on a work trip to Hiroshima, Tsutomu and his colleagues were discussing buying tickets to return home the next day when he realized he had forgotten his name stamp—the personal seal Japanese people still use to sign official documents. He ran back to retrieve it, but while walking through a field toward the factory, Tsutomu was suddenly hurled into the air by a tremendous blast. He fled past bodies floating in rivers and others so charred it was impossible to know if they were men or women. He barely escaped with his life.

Thousands of feet above, the men who dropped the untested uranium bomb were relieved: Ari’s grandfather, radar operator Jacob Beser, and his comrades weren’t even sure the bomb would work, let alone if they would survive its blast. But through a maneuver they had practiced countless times, they too escaped with their lives. He later said of the mushroom cloud that it looked like sand billowing in shallow water.

When Tsutomu returned home to Nagasaki and warned others about what had happened, and what he thought could happen there, the second bomb detonated, albeit off target. He did not realize that where he stood, at the Mitsubishi Heavy Industries Office in Mizunoura, Nagasaki was part of a complex of Mitsubishi buildings that had been the intended target. Through a series of unlucky mishaps and errors by the crew of the B-29 Bockscar and knowing that he needed to duck when he saw the flash of an atomic bomb, he survived again. He would later say that these mushroom clouds were following him.

Jacob, the only serviceman who flew both bombing missions, prayed it wouldn’t happen again. At the time, the men on the planes and the scientists who built the bombs believed they were ending the war and saving lives. That belief shaped how the story of nuclear weapons was told for generations—in classrooms, in commemorations, even in our families.

But decades later, historians uncovered a more complicated and less pleasant picture: Japan had already signaled willingness to surrender if the emperor could be preserved, and the Soviet entry into the war against Japan also played an instrumental role in forcing Japan’s surrender. World War II could well have ended without nuclear hellfire or a costly US ground invasion, but that path was never taken, and so the mushroom clouds rose anyway, casting a shadow over humanity.

Jacob and Tsutomu never met. Their fates intersected only in us, their grandchildren.

We met in 2013 and began a dialogue that has lasted over a decade. We didn’t face each other with ease. Ari feared he was brought to Kosuzu’s home to be blamed. Kosuzu saw only Jacob Beser, the man on the planes. But we realized we were our own people.

We kept talking and exchanging letters—some published in Japan, many more private. Our dialogue forced us to confront not just each other’s truths, but also the narratives we had inherited from our countries. We never reached an easy agreement, for the two experiences may not be fully reconcilable. But we discovered that we have more in common than what divides us, and that friendship is forged not by avoiding pain, but by walking through it together. Over time, our letters stopped being about “the bomber” and “the survivor.” They became about two people searching for a way forward.

Our grandfathers are gone. Most atomic bombing survivors, or hibakusha, are in their 80s and 90s. Soon, there will be no more living witnesses to August 1945. Their memory is passing to people like us: descendants, inheritors of trauma and responsibility. We did not ask for this baton, but we carry it because silence is dangerous. The nuclear danger our grandparents knew has not faded; it has evolved and grown. Public memory is fraying just as the risk of nuclear war rises again.

As long as nuclear weapons exist, every generation needs a version of our grandfathers’ story to understand why we must have peace. That is why we joined together to write our own book, published first in Japanese. We want to demonstrate that even through the most violent chapters in human history, the next generations can still find a way to get along and cut the cycle of violence.

We both hold a determination to realize our grandfathers’ shared belief in a world free of nuclear weapons. In Jacob’s speeches and interviews, he often called Hiroshima and Nagasaki “the worst act of man’s inhumanity to his fellow man.” While he never apologized, he was not proud of his role. Tsutomu did not speak about his experiences until he was 90. But he believed, and often said, “The truth starts as a whisper, but we must keep telling it. The truth transcends borders.”

We are told that deterrence—almost 10,000 nuclear weapons owned by nine nations pointed at each other—keeps us safe. But peace maintained by the threat of annihilation is fragile at best. From Ukraine to Iran, to East Asia, the same logic claimed to have ended World War II now underwrites the most dangerous standoff in human history.

Our friendship offers an alternative. It does not erase what happened—both the Japanese wartime atrocities and US atomic bombings—and it does not absolve anyone. Instead, it proves, in the smallest human way, that even inherited enemies can pass their trauma and become friends. If two people bound by the most violent act in human history can learn to listen and speak, then nations can too.

We still live in the shadow of the mushroom clouds of Hiroshima and Nagasaki. Whether the nuclear shadow defines the next century or humans save themselves and their children from it depends on whether world leaders and their populations choose to face each other across borders as human beings rather than as enemies. Our story proves that dialogue and reconciliation are possible even across the deepest divides. Eighty years after the atomic bombings, it’s time that people demand their leaders to do the same—and recommit to their moral and legal obligations to nuclear disarmament.