On the problem that the United States dropped atomic bombs on Hiroshima and other areas in Japan.

At that time, the United States successively won midway and Guadalcanal, and then won the battles of Saipan and Iwo Jima after paying a heavy price. At this time, the U.S. high command considered bombing important Japanese cities with B-29 heavy bombers, and then the U.S. military forcibly landed on the Japanese island for occupation, but it proved that this method was not feasible. Because the Japanese army is educated by the spirit of Bushido, all Japanese soldiers will not surrender, but will only fight the American army to the end, so that the American army will definitely win the battle, but the casualties will be very huge. Unlike European soldiers, Japanese soldiers surrender if they can't beat them.

At that time, American physicist Oppenheimer led American volunteers to invent the atomic bomb. At the same time, Truman, who took over as president of the United States, thought twice and could not sacrifice too many American soldiers. At the same time, in order to avenge the 3000 American soldiers killed by the Japanese attack on Pearl Harbor, he decided to bomb major cities in Japan. At first, he thought it was Tokyo and Ogura Arsenal, but the former was worthless because of the bombing, and the latter chose Hiroshima and Nagasaki because of the bad weather at that time. This is to end the war at an early date and avoid unnecessary casualties.