TOKYO >> Two very different visions of the hell that is war are seared into the minds of World War II survivors on opposite sides of the Pacific.

Michiko Kodama saw a flash in the sky from her elementary school classroom on Aug. 6, 1945, before the ceiling fell and shards of glass from blown-out windows slashed her. Now 78, she has never forgotten the living hell she saw from the back of her father, who dug her out after a U.S. military plane dropped an atomic bomb on the city of Hiroshima, Japan.

Severely burned people were walking like zombies, asking for help, for water. A little girl looked into Michiko’s eyes, then collapsed.

Lester Tenney saw Japanese soldiers killing fellow American captives on the infamous Bataan Death March in the Philippines in 1942. “If you didn’t walk fast enough, you were killed. If you didn’t say the right words, you were killed, and if you were killed you were either shot to death, bayonetted or decapitated,” the 95-year-old veteran said.

Different experiences, different memories are handed down, spread by the media and taught in school. Collectively, they shape the differing reactions in the United States and Japan to Barack Obama’s decision to become the first sitting American president to visit the memorial to atomic bomb victims in Hiroshima later this week.

The U.S. dropped a second atomic bomb on Nagasaki three days after Hiroshima, and Japan surrendered six days later, bringing to an end a bloody conflict that the U.S. was drawn into after Japan’s attack on Pearl Harbor.

Japan identifies mostly as “a victim rather than a victimizer,” said Stephen Nagy, an international-relations professor at the International Christian University in Tokyo. “I think that represents Japan’s regional role and its regional identity, whereas the United States has a global identity, a global agenda and global presence. So when it views the bombing of Hiroshima, Nagasaki, it’s in the terms of a global narrative, a global conflict the United States was fighting for freedom or to liberate countries from fascism or imperialism. To make these ends meet is very difficult.”

A poll last year by the Pew Research Center found that 56 percent of Americans believe the use of nuclear weapons was justified, while 34 percent do not. In Japan 79 percent said the bombs were unjustified, and only 14 percent said they were.

Terumi Tanaka, an 84-year-old survivor of the Nagasaki bombing, said of Obama, “I hope he will give an apology to the atomic bomb survivors, not necessarily to the general public. There are many who are still suffering.”

The White House has clearly ruled out an apology, which would inflame many U.S. veterans and others, and said that Obama would not revisit the decision to drop the bombs.

“A lot of these people are telling us we shouldn’t have dropped the bomb — hey, what they talking about?” said Arthur Ishimoto, a veteran of the Military Intelligence Service, a U.S. Army unit made up of mostly Japanese-Americans who interrogated prisoners, translated intercepted messages and went behind enemy lines to gather intelligence.

Now 93, he said it’s good for Obama to visit Hiroshima to “bury the hatchet,” but there’s nothing to apologize for. Ishimoto, who was born in Honolulu and rose to be an Air Force major general and commander of the Hawaii National Guard, believes he would have been killed in an invasion of Japan if Japan had not surrendered.

“It would have been terrible,” he said. “There is going to be controversy about apologizing. I don’t think there should be any apology. … We helped that country. We helped them out of the pits all the way back to one of the most economically advanced. There’s no apology required.”

Beyond the deaths — the atomic bombs killed 140,000 people in Hiroshima and 73,000 in Nagasaki — the effects of radiation have lingered with survivors, both physically and mentally.

Kodama, the Hiroshima schoolgirl, faced discrimination in employment and marriage. After her first love failed because her boyfriend’s family said they didn’t want “radiated people’s blood in their family,” she married into a more understanding one.

The younger of her two daughters died of cancer in 2011. Some say she shouldn’t have given birth, even though multigenerational radiation effects have not been proven.

Obama doesn’t have to apologize, Kodama said, but he should take concrete actions to keep his promise to seek a nuclear-free world.

“For me the war is not over until the day I see a world without nuclear weapons.” she said. “Mr. Obama’s Hiroshima visit is only a step in the process.”

Nagasaki survivor Tanaka views the atomic bombings as a crime against humanity. A promise by Obama to survivors to do all he can for nuclear disarmament “would mean an apology to us,” he said.

He added that his own government should take some of the blame for the suffering of bomb victims. “It was the Japanese government that started the war to begin with and delayed the surrender,” he said, adding that Japan has not fully faced up to its role in the war.

Tenney, one of only three remaining POWs from the Bataan Death March, wants Obama in Hiroshima to remember all those who suffered in the war, not just the atomic bomb victims.

“From my point of view, the fact that the war ended when it did and the way it did, it saved my life and it saved the life of those Americans and other Allied POWs that were in Japan at the time,” he said at his home in Carlsbad, Calif. “I was in Japan, shoveling coal in a coal mine. No one ever apologized for that.”