Why the bombing?

Why did the USA drop atom bombs on Japan? (from Wikipedia)

Even before the surrender of Nazi Germany on May 8, 1945, plans were underway for the largest operation of the Pacific War, Operation Downfall, the Allied invasion of Japan. The operation had two parts: Operation Olympic and Operation Coronet. Set to begin in October 1945, Olympic involved a series of landings by the U.S. Sixth Army intended to capture the southern third of the southernmost main Japanese island, Kyūshū. Operation Olympic was to be followed in March 1946 by Operation Coronet, the capture of the Kantō Plain, near Tokyo on the main Japanese island of Honshū by the U.S. First, Eighth and Tenth Armies, as well as a Commonwealth Corps made up of Australian, British and Canadian divisions. The target date was chosen to allow for Olympic to complete its objectives, for troops to be redeployed from Europe, and the Japanese winter to pass.

Japan's geography made this invasion plan obvious to the Japanese; they were able to predict the Allied invasion plans accurately and thus adjust their defensive plan, Operation Ketsugō, accordingly. The Japanese planned an all-out defense of Kyūshū, with little left in reserve for any subsequent defense operations.Four veteran divisions were withdrawn from the Kwantung Army in Manchuria in March 1945 to strengthen the forces in Japan, and 45 new divisions were activated between February and May 1945. Most were immobile formations for coastal defense, but 16 were high quality mobile divisions. In all, there were 2.3 million Japanese Army troops prepared to defend the home islands, backed by a civilian militia of 28 million men and women. Casualty predictions varied widely, but were extremely high. The Vice Chief of the Imperial Japanese Navy General Staff, Vice Admiral Takijirō Ōnishi, predicted up to 20 million Japanese deaths.

On June 15, 1945, a study by the Joint War Plans Committee, who provided planning information to the Joint Chiefs of Staff, estimated that Olympic would result in 130,000 to 220,000 U.S. casualties, with U.S. dead in the range from 25,000 to 46,000. Delivered on June 15, 1945, after insight gained from the Battle of Okinawa, the study noted Japan's inadequate defenses due to the very effective sea blockade and the American firebombing campaign. The Chief of Staff of the United States Army, General of the Army George Marshall, and the Army Commander in Chief in the Pacific, General of the Army Douglas MacArthur, signed documents agreeing with the Joint War Plans Committee estimate.

The Americans were alarmed by the Japanese buildup, which was accurately tracked through Ultra intelligence. Secretary of War Henry L. Stimson was sufficiently concerned about high American estimates of probable casualties to commission his own study by Quincy Wright and William Shockley. Wright and Shockley spoke with Colonels James McCormack and Dean Rusk, and examined casualty forecasts by Michael E. DeBakey and Gilbert Beebe. Wright and Shockley estimated the invading Allies would suffer between 1.7 and 4 million casualties in such a scenario, of whom between 400,000 and 800,000 would be dead, while Japanese fatalities would have been around 5 to 10 million.

IN OTHER WORDS ........

• By early 1945, it was clear that the war was lost for Japan. By 1943, the U.S. was producing almost 100,000 aircraft a year, compared to Japan's production of 70,000 for the entire war. By the middle of 1944, the U.S. had almost a hundred aircraft carriers in the Pacific, far more than Japan's twenty-five for the entire war. But there was no sign of a surrender.
  
  
• In April 1945, American forces landed on Okinawa, where heavy fighting continued until June. Although some Japanese soldiers were taken prisoner, most fought until they were killed or committed suicide. Nearly 99% of the 21,000 defenders of Iwo Jima were killed. Of the 117,000 Okinawan and Japanese troops defending Okinawa in April–June 1945, 94% were killed and 7,401 surrendered, an unprecedentedly large number.
  
  
• It was estimated that a full-scale invasion of Japan would suffer between 1.7 and 4 million casualties, of whom between 400,000 and 800,000 would be dead, while Japanese fatalities would have been around 5 to 10 million.
  
  
• In the early months of 1945, the XXI Bomber Command under LeMay firebombed 67 Japanese cities. The firebombing of Tokyo, codenamed Operation Meetinghouse, on March 9–10 killed an estimated 100,000 people and destroyed 16 square miles (41 km²) of the city and 267,000 buildings in a single night. It was the deadliest bombing raid of the war, at a cost of 20 B-29s shot down by flak and fighters. By May, 75% of bombs dropped were incendiaries designed to burn down Japan's "paper cities". By mid-June, Japan's six largest cities had been devastated.
  
  
• In early May 1945, the Interim Committee was created by Stimson at the urging of leaders of the Manhattan Project and with the approval of Truman to advise on matters pertaining to nuclear energy. During the meetings on May 31 and June 1, scientist Ernest Lawrence had suggested giving the Japanese a non-combat demonstration. Arthur Compton later recalled that "it was evident that everyone would suspect trickery. If a bomb were exploded in Japan with previous notice, the Japanese air power was still adequate to give serious interference. An atomic bomb was an intricate device, still in the developmental stage. Its operation would be far from routine. If during the final adjustments of the bomb the Japanese defenders should attack, a faulty move might easily result in some kind of failure. Such an end to an advertised demonstration of power would be much worse than if the attempt had not been made. It was now evident that when the time came for the bombs to be used we should have only one of them available, followed afterwards by others at all-too-long intervals. We could not afford the chance that one of them might be a dud. If the test were made on some neutral territory, it was hard to believe that Japan's determined and fanatical military men would be impressed. If such an open test were made first and failed to bring surrender, the chance would be gone to give the shock of surprise that proved so effective. On the contrary, it would make the Japanese ready to interfere with an atomic attack if they could. Though the possibility of a demonstration that would not destroy human lives was attractive, no one could suggest a way in which it could be made so convincing that it would be likely to stop the war!
  
  
• The Nuclear Target Committee nominated five targets: Kokura (now Kitakyushu), the site of one of Japan's largest munitions plants; Hiroshima, an embarkation port and industrial center that was the site of a major military headquarters; Yokohama, an urban center for aircraft manufacture, machine tools, docks, electrical equipment and oil refineries; Niigata, a port with industrial facilities including steel and aluminum plants and an oil refinery; and Kyoto, a major industrial center. These cities were largely untouched during the nightly bombing raids and the Army Air Forces agreed to leave them off the target list so accurate assessment of the damage caused by the atomic bombs could be made. Hiroshima was described as "an important army depot and port of embarkation in the middle of an urban industrial area. It is a good radar target and it is such a size that a large part of the city could be extensively damaged. There are adjacent hills which are likely to produce a focusing effect which would considerably increase the blast damage. Due to rivers it is not a good incendiary target."
  
  
• At 8:16 a.m. on August 6 1945 (Japanese time), an American B-29 bomber, the Enola Gay, dropped the world’s first atom bomb over the city of Hiroshima.
  
  
• On August 7, a day after Hiroshima was destroyed, Dr. Yoshio Nishina and other atomic physicists arrived at the city, and carefully examined the damage. They then went back to Tokyo and told the cabinet that Hiroshima was indeed destroyed by a nuclear weapon. Admiral Soemu Toyoda, the Chief of the Naval General Staff, estimated that no more than one or two additional bombs could be readied, so they decided to endure the remaining attacks, acknowledging "there would be more destruction but the war would go on". American Magic codebreakers intercepted the cabinet's messages.
  
  
• On August 8, the USSR declared war on Japan, and on August 9, a second bomb fell on Nagasaki, but STILL there came no surrender.
  
  
• The Emperor's call to stop fighting came a full SIX DAYS after the bombing of Nagasaki.

Some of the Immediate Effects and Aftermath

• Approximately 75,000 people were killed immediately as a direct result of the blast, and another 35,000 were injured. At least another 60,000 would be dead by the end of the year from the effects of the fallout.
  
  
• Over 90% of the doctors and 93% of the nurses in Hiroshima were killed or injured—most had been in the downtown area which received the greatest damage. The hospitals were destroyed or heavily damaged. Only one doctor, Terufumi Sasaki, remained on duty at the Red Cross Hospital.
  
  
• More than 80,000 Koreans were living in Hiroshima on Aug. 6, 1945. Most had been compelled to leave Korea (a Japanese colony at the time) to work as forced laborers in Japan before and during World War II. More than 20,000 Koreans died in the blast, about 1 in 5 of the victims.
  
  
• In Japan, survivors became known as “hibakusha,” or “bomb person.” Initially a pejorative term, hibakusha carried a stigma because many Japanese feared exposure to the bomb’s radiation had contagious and hereditary effects. Families who believed survivors’ exposure to radiation would cause prenatal problems blocked marriages. Employers ignored survivors’ job applications because they thought all survivors experienced lethargy. There was some truth to this. In addition to the burns, the bomb’s effects gave survivors radiation sickness, which caused chronic lethargy and diarrhea, acute symptoms that lasted for months.
  
  
• Twelve American airmen were imprisoned at the Chugoku Military Police Headquarters, about 1,300 feet (400 m) from the hypocenter of the blast.Most died instantly, although two were reported to have been executed by their captors, and two prisoners badly injured by the bombing were left next to the Aioi Bridge by the Kempei Tai, where they were stoned to death. Eight U.S. prisoners of war killed as part of the medical experiments program at Kyushu University were falsely reported by Japanese authorities as having been killed in the atomic blast as part of an attempted cover-up.
  
  
• Ian Buruma observed, "News of the terrible consequences of the atom bomb attacks on Japan was deliberately withheld from the Japanese public by US military censors during the Allied occupation—even as they sought to teach the natives the virtues of a free press. Casualty statistics were suppressed. Film shot by Japanese cameramen in Hiroshima and Nagasaki after the bombings was confiscated.
  
  "Hiroshima", the account written by John Hersey for The New Yorker, narrates the stories of six bomb survivors immediately prior to and four months after the dropping of the Little Boy bomb. The book had a huge impact in the US, but was banned in Japan. As John Dower says: 'In the localities themselves, suffering was compounded not merely by the unprecedented nature of the catastrophe, but also by the fact that public struggle with this traumatic experience was not permitted."
  
  The US occupation authorities maintained a monopoly on scientific and medical information about the effects of the atomic bomb through the work of the Atomic Bomb Casualty Commission, which treated the data gathered in studies of hibakusha as privileged information rather than making the results available for the treatment of victims or providing financial or medical support to aid victims.
  
  
• TRAMS were running in areas outside the immediate bomb blast just THREE DAYS after the bomb was dropped. Some of those trams are STILL operating today, including the famous 652. I took this photo in June 2019.

"This was the first flower to blossom from the atomic bomb-scorched earth that had been supposed incapable of supporting plantlife for 75 years. As such it gave hope and strength to the city residents as they poured their utmost efforts into rebuilding the city. It blooms in the summertime, especially around the time of the anniversary of the atomic bombing, when the flowers reach full bloom and reawaken deep emotions as they vie to surpass one another in beauty."