It was a fine, clear day in Hiroshima on Aug. 6, 1945. That fact determined the fate of the city, together with its numerous inhabitants.
Given the perfect weather conditions there, a B-29 Superfortress bomber nicknamed the Enola Gay headed for the city, skipping the other two potential targets: the cities of Nagasaki and Kokura, Fukuoka Prefecture.
At 8:15 a.m., the Enola Gay dropped the bomb. Forty-two seconds later, it exploded, its blinding flash as bright as the sun.
The fireball grew to 280 meters in diameter and caused the temperature at ground zero to jump to 3,000 to 4,000 degrees Celsius. It instantly vaporized many humans who had the misfortune of being under it at that time.
Before the nuclear attack, Hiroshima was home to an estimated 280,000 to 290,000 civilians and some 43,000 military personnel. The overwhelming blast, heat and radiation of the uranium bomb was blamed for the deaths of an estimated 140,000 of those people by the end of the year.
The visit to Hiroshima by U.S. President Barack Obama this Friday has revived a long-standing debate that has deeply split both Japanese and Americans throughout the postwar years: were the nuclear attacks in Hiroshima and Nagasaki necessary? Could the mass killings be justified in one way or another?
Historians have been sharply divided over this key question.
American historians in the past tended to say, echoing President Harry Truman after the war, that the bombings brought the conflict to an early close and saved the lives of hundreds of thousands of American soldiers — possibly even a million — who otherwise would have been killed in the planned attacks on the Japanese mainland.
But in the 1980s, some revisionist historians in the U.S. started challenging that argument, claiming the projected fatalities of the U.S. landing operation would have been much lower — maybe in the tens of thousands — in a realistic scenario.
These historians claimed the main and hidden motivation for Truman to use nuclear weapons was to demonstrate U.S. power to the former Soviet Union since by that time the Cold War had already started.
Indeed, by around June 1945 Japan’s military, economy and industry had all been extensively eroded, experts say. Based on detailed studies of wartime damage, the 1946 U.S. Strategic Bombing Survey concluded that “Japan would have surrendered even if the atomic bombs had not been dropped.”
That survey, however, may have reached its conclusion only in hindsight.
Seventy years after the dropping of the atomic bombs, the academic debate is still going on due to the apparent lack of decisive evidence to support either side.
Polls have shown the Japanese and American public are still likewise split over the issue.
According to a 2015 survey by the Washington-based Pew Research Center, 56 percent of Americans believe the atomic bombings were justified, while only 14 percent of Japanese hold the same opinion.
Akira Yamada, a professor of modern Japanese history at Tokyo’s Meiji University, said both Japanese and Americans tend not to focus on facts “inconvenient” for themselves in remembering and discussing the conflict.
For example, many Japanese ignore details about the war crimes committed by the Japanese military during the war with China and during the Pacific War, he said.
On the other hand, American people tend to pay less attention to the inhumane nature of the use of nuclear weapons and the massive indiscriminate U.S. air raids during the Pacific War, which killed many Japanese noncombatants across the country, Yamada said.
The 1946 U.S. bombing survey estimated that the total number of civilian casualties in Japan as a result of nine months of air attacks was 806,000. Of these, about 330,000 were fatalities, according to the report.
Some Japanese historians put the number of fatalities much higher, at around 600,000 to 700,000. An air raid carried out on the night of March 10, 1945, was alone estimated to have killed about 100,000 people in Tokyo, based on records of cremations by the Tokyo Metropolitan Government.
“Indiscriminate attacks on general citizens are prohibited by international law. One of the most serious cases of this is use of a nuclear weapon,” Yamada maintained.
Yamada, however, quickly added that the Japanese military likewise carried out many massive air raids on Chinese cities, including Chongqing, in the southwest, and committed many war atrocities.
“It’s difficult to pass down collective memories of certain facts that people find inconvenient for themselves. And we sometimes fail to do so,” Yamada said.
For many Americans, in particular veterans who fought against Japan, the Pacific War is remembered as a “good war” against the evil fascism of Nazi Germany and Imperial Japan.
Thus, Americans tend to view the atomic bombings as ending the war and saving the lives of numerous American soldiers, said Satoshi Fujita, a research associate at Meiji University who has studied history textbooks used by American high schools and colleges.
Meanwhile, in Japan, more people regard the atomic bombings of Hiroshima and Nagasaki as the beginning of the nuclear age, an aspect of the Cold War confrontation between the U.S. and the Soviet Union, Fujita pointed out.
Still, Fujita notes that, particularly after the mid-1990s, an increasing number of history textbooks in the U.S. have addressed the controversy over the justification of using the atomic bombs against Japan, he said.
“This change in America probably reflects generational changes of its society,” Fujita said.
Polls appear to back up Fujita’s observations.
In 1945, a Gallup poll conducted immediately after the bombings found that 85 percent of Americans approved of the atomic attacks on Hiroshima and Nagasaki.
This approval rate had fallen to 63 percent in a 1991 Detroit Free Press survey and then to 56 percent in a 2015 Pew Research Center poll.
However, Scott Sagan, a professor of political science at Stanford University, has a different view of the poll results.
The change might simply be a reflection of the drastic transformation in American views of Japan — now a close friend and ally of the United States — in the postwar years, not a change in their attitude toward the use of nuclear weapons, he said.
Sagan and his fellow researchers asked research firm YouGov last July to survey a sample of 620 Americans about a mock war scenario with Iran.
The scenario was carefully prepared to create a 21st century version of Japan’s 1945 surprise attack on Pearl Harbor.
In it, Tehran has attacked a U.S. aircraft carrier, killing 2,403 military personnel — the same number of casualties as in the Pearl Harbor attack — after it was caught violating the 2015 nuclear deal.
The result was startling for Sagan.
When pressed to choose from two options: to carry out an attack against Iran that would sacrifice the lives of 20,000 American soldiers, or to drop a single nuclear weapon on a major city near Tehran, killing an estimated 100,000 Iranian civilians, the survey showed 59 percent of respondents backed using a nuclear bomb to attack a city.
The result indicated that, when provoked, Americans today could encourage their president to use a nuclear weapon, rather than constrain their leader, Sagan said during a telephone interview with The Japan Times.
“We should not enter into a blame game to discuss who should apologize to whom for what,” Sagan said when asked about Obama’s visit to Hiroshima this week.
Rather than focusing too much on historical issues, we should be more future-oriented and try to reduce the possibilities of a nuclear war and reaffirm our commitment not to deliberately attack noncombatants during a war, Sagan argued.
In that sense, Obama’s visit to Hiroshima may be just one small step toward a safer world with fewer nuclear weapons as well as total postwar reconciliation between Japan and the United States.
Tsuyoshi Hasegawa is a highly respected historian at the University of California, Santa Barbara, who in 2005 published an award-winning book that argues it was the entry of the Soviet Union into the war, not the U.S. atomic bombs, that shocked top Japanese leaders most and forced the country to surrender.
Hasegawa’s theory indicated that the use of the atomic bombs in fact did little to help bring the war to an early close. Hasegawa himself believes the use of nuclear weapons is inhuman and violates international law, which bans the use of cruel weapons.
Still, Hasegawa believes Obama should not extend an apology while in Hiroshima.
In his view, the Japanese people have yet to form a national consensus on Japan’s past wars of aggression, and some people still try hard to justify them.
“The government couldn’t make any decision until the Emperor stepped in to make a ‘sacred decision’ to end the war. Why was the war prolonged and atomic bombs dropped? Japanese people should first think about the responsibility of their own government” before demanding an apology from an American leader, Hasegawa said.
He was referring to Emperor Hirohito, known posthumously as Emperor Showa.