KOBE - The United States dropped 49 mock atomic bombs across Japan in the closing weeks of World War II, killing around 400 people as American air crews practiced the techniques later used in the atomic bombing of Hiroshima.
The weapons, built in the same shape as the atomic bomb and weighing about 4.5 tons, were approximately three meters long. Their rounded form led them to be known as "Pumpkin" bombs.
Paul Tibbets, the U.S. pilot who commanded the mission that dropped the atomic bomb on Hiroshima 81 years ago, later said the practice missions were essential to the operation's success. "The operation required accuracy. That is why we used practice bombs," he said. Asked whether the training was effective, he replied, "It was extremely effective."
Documents left by the United States show the importance placed on such rehearsals. One document stated that successfully carrying out an atomic bomb operation required a complete rehearsal of the entire mission.
Tests had shown that accurately dropping such an unusually large bomb was difficult. Footage from American bombing trials showed bombs missing their intended targets by considerable distances, while their size made their trajectory during descent unstable.
Because the atomic bomb would be used for the first time in human history, American planners required crews to be able to deliver it accurately to a designated point. The United States therefore produced conventional bombs shaped like the atomic weapon and used them for practice missions over Japan.
The Pumpkin bombs were dropped at locations across the country, including much of the Kansai region. Nara was the only area in Kansai not targeted.
Koki Nishioka, a graduate student at Kobe University who researches the mock atomic bombs, said the missions represented an important step in the development of the U.S. atomic bombing operation.
He said the experience accumulated through Pumpkin bombing missions provided practical knowledge to the American unit assigned to atomic attacks.
Nishioka became interested in the subject after seeing an exhibition in Hiroshima explaining that cities including Osaka and Kobe also had connections to the atomic bomb program. "I was shocked when I saw that cities such as Osaka and Kobe were also connected with the atomic bomb," he said.
A replica of one of the bombs is displayed at a museum in Fukui Prefecture, where visitors have expressed surprise that the weapons were dropped so widely across Japan.
One visitor said the subject had previously seemed distant. "I never thought I had any connection with something like this. I was a little surprised. I had thought it didn't really have anything to do with us."
Residents who experienced the attacks remember scenes of severe destruction.
One survivor, Tachibana, lived near a location where one of the bombs fell. Tachibana recalled people being taken to an elementary school covered in blood and described diving into a nearby structure as the blast shattered glass and damaged surrounding buildings.
Damage from the explosion remains visible decades later, including a structure that is still tilted by the force of the blast.
Tachibana questioned how those carrying out the bombing could knowingly drop a weapon where people were present. "There were people there, and they dropped it and people died. I wonder what they thought about that as human beings. It is difficult to understand."
At another bombing site, a factory remains in operation today near the area recorded as the impact point.
At the time, the facility was a military factory producing equipment including torpedoes, and military personnel and employees were among those killed.
Documents discovered last year in a warehouse in Shizuoka Prefecture provided detailed records of the damage caused there.
Researchers said the records show how casualty figures changed during the confusion following the attack, including reports in which the number of victims was revised from six to eight.
One account described injured people emerging covered in blood from between destroyed buildings, calling the scene both a battlefield and a place of devastation.
American military records, however, described the mission in very different terms, reporting an "excellent result."
Kobe was struck by four Pumpkin bombs, but the exact impact point of one of them remains unknown.
Nishioka has been working to determine where that bomb fell.
The target was an industrial area that included a Kobe Steel factory, and Nishioka said the aircraft involved in the bombing was the Enola Gay, which would later carry out the atomic bombing of Hiroshima.
For the Enola Gay, he said, the Kobe operation was its first mission over Japan and effectively represented an early step toward Hiroshima. "An operation that can truly be regarded as the first step toward the atomic bombing of Hiroshima was being carried out in the skies over Kobe," Nishioka said.
Using wartime diaries and other surviving records, Nishioka initially estimated that the missing bomb had fallen in a mountainous area.
He examined a photograph taken in 1946 that showed northern Kobe and identified what appeared to be a possible impact mark.
Three years ago, he conducted a field survey using a small metal detector, inserting it into the ground to look for buried fragments.
Several pieces of metal believed to have come from bombs were discovered.
Nishioka said finding wartime material still preserved underground after so many decades gave him a strong sense of the weight of history.
Subsequent analysis of the fragments showed that although they came from bombs, they were not from the missing Pumpkin bomb.
Nishioka has since revised his estimate based on documentary descriptions and is continuing his investigation in another area of Kobe.
He said the research demonstrates that the history of the atomic bomb is not limited to Hiroshima and Nagasaki but remains embedded in communities across Japan through the Pumpkin missions.
"History connected with the atomic bomb is still buried in places close to us through these Pumpkin bombs," Nishioka said. "The problem of nuclear weapons continues in international society today, so I hope this can also become an opportunity to look at that issue again."
After the war, Tibbets was repeatedly asked how he viewed his role in the Hiroshima bombing.
Asked whether he was proud of what he had done, he answered, "Yes, I am."
He later maintained the same position, saying that even after many years his answer had not changed and that he believed the atomic bomb had brought peace to the world at the time.
Nearly 10,000 nuclear weapons remain in existence around the world today.
Source: KTV NEWS
