Here are explanations:
To put an immediate end to the war
The USA was facing the prospect of invading Japan to subdue it. The last few battles, Iwo Jima and Okinawa particularly, were incomprehensibly bloody. Japan had no regard for its own citizens' lives and planned to turn their whole island into a fortress. It was estimated that casualties would be 1 million Americans and half a million British in the first invasion alone. Some cynics say we used it to scare Stalin as well, but the fact remains that they ignored an ultimatum on 27 July 1945 after enduring the worst conventional bombs could do. A powerful argument remains that the Bomb saved allied and Japanese lives.
The Allies demanded unconditional surrender of the Axis. In the Pacific Theater, the Allies, led by the United States, rolled up the Japanese expansion island by island. When Guam was taken, the Allies had a base from which stage an invasion. The estimates of American casualties for an invasion of mainland Japan was in excess of 1 million Americans. Possibly in excess of 2 million Americans. The United States dropped two atomic bombs to save American lives and speed the end of the war. Prior to using the atomic bomb, Japan was given ultimatums to surrender along with warnings of the dire consequences. The Japanese government ignored the warnings. While the use of the atomic bomb was a technological and strategic turning point in both WWII and all future diplomatic and strategic activities, there were more people killed, maimed, and injured during the Tokyo firebombing campaigns than by the atomic bomb.
To force Japan to surrender without further fighting. Japan surrendered very quickly thus saving the lives of over 100,000 American soldiers and perhaps as many as 1,000,000 Japanese who would have died if we had invaded Japan.
The Allies utilized atomic weapons to bring Japan to her knees. As an American, how hard would you fight an enemy if they were invading our nation? I mean literally on the soil of our 50 states? Then imagine how hard EVERY Japanese citizen, man, woman AND child, would be trying to kill OUR men, as we invade their nation.
Tensions were starting to build up in Europe between Soviet Union and its western allies. Since USSR had an overwhelming numerical superiority there, a show of force was needed to convince Stalin to "behave". Besides, the Russians were preparing for an invasion of Japan. I think these considerations were at least as valid back then as saving American lives.
According to some sources, Japan had a military force of over 9 million soldiers. Through battles like Midway, Okinawa, Iwo Jima, Guadacanal, and other "island-hopping" battles, 1.5 million soldiers either were killed or wounded enough so they couldn't fight. That meant that if Operation Olympic (the invasion of the main island of Japan) were to occur we would have to fight every soldier we had defeated before four times over! Even if we hadn't of dropped the atomic bomb, Hiroshima and Nagasaki would still have been targets for attack. This is because Hiroshima was a large industrial city that contained the 2nd Japanese Army Headquarters, which was in charge of all the defense systems in Southern Japan; Hiroshima also had communication centers for armies, storage points, and troop assemblies. Small industrial plants were also in the outskirts of the city. As for Nagasaki, it was the largest fully operational sea port in Southern Japan, which produced ships, equipment, and relief supplies. There is much other information that can be explained about the reality of dropping the bomb on Japan and this was one 'chunk' of information.
I agree with the guys who were talking about conserving American army resources and manpower. At Iwo Jima there were nearly 30,000 marines KIA. The Japanese lost nearly all of their army there. Imagine that in a place with cities, etc and bigger armies in a homeland .Even if you guys won, the Japanese would never forgive you. More deaths would have been caused than the bombs, and in more cities. The fact that a lot of Japanese fought to the death because they were never given a chance to surrender, and the fact that after Pearl harbor 13% of Americans said in a poll (13% of voting Americans, that is) that the only acceptable outcome of the war to them was the death of every Japanese man woman and child. Then there are slogans like, "kill japs, kill japs and kill more japs) and somebody said how the main language in Hell by the end would be Japanese. The Yanks were furious for Pearl Harbor and revenge is the most dangerous reason for fighting for both sides. The Japanese are brave people who see honor in death if the death is good (not in all death, though. Any fool can die in battle. True courage is living when it is right to live and dying when it is right to die). So, IMO, the A-bomb was used to reduce the expected casualty rate and loss of resources (tanks, weapons, etc all cost the taxpayers and government a lot of money) and I'm guessing it probably did for both sides.
World War two ended on August 10, 1945 only four after the Little Boy uranium bomb was dropped on Hiroshima and one day after the Fat Man plutonium bomb was dropped on Nagasaki. Combined, approximately 128,000 died just due to the massive concussion and explosions caused by the bombs, and about 120,000 suffered from radiation sickness and cancer, many of whom died afterwards. The question is, was it really necessary to drop two atomic bombs on Japan to get them to surrender? My answer is yes, because of several factors. One is the culture of the Japanese at the time. For centuries the Japanese had a warrior class called the samurai. The samurai followed Bushido, or the way of the warrior, which was an honor code that preaches that honor, duty, and loyalty to the emperor and local warlord are the absolute virtues that can be achieved. As a result, a loss of honor would mean that the dishonored samurai would be expected to commit Seppuku, or ritualistic suicide, which involves a samurai taking his sword, stabbing himself with it, and cutting out his own liver. The wound was very painful and could take quite a while to die from, anywhere from a few minutes to a week. The most common way in which a samurai could be dishonored would be by being defeated in battle. However, fighting to the last man and arrow (or in this case, round of ammo) and holding ones position till the death was considered a great honor. Does this sound like a nation that is willing to give up? By the last years of the war, everyone, men and women, over the age of thirteen was a part of a sort of National Guard, and were under the same rules as the rest of the military, which was in turn fighting under a modified code of Bushido which dictated that they never surrender and leave behind the wounded. Another aspect of Japan's culture was that of a group mentality. About ninety-nine percent of the Japanese people were, at the time of World War Two, direct decedents from the original nomadic Mongolian tribes that crossed over into Japan from the Korean Peninsula. They inhabited a land of which only twenty percent was flat enough to farm. Entire towns had to work together to maintain tiny rice paddies carved into hillsides that were irrigated by a community network. Disagreement among the common people against their ruler or with each other was unthinkable and impractical. On the whole, as long as the military oligarchy wanted the war to continue, the majority of the people would be willing to follow through. The Nuclear Bombs being dropped finally got the military oligarchy to be willing to give up the fighting, and that is what brought them to the peace table, under the condition that the emperor remain in power. Even after the bombs were dropped, the Emperor's speech never mentioned surrender; just that it was in the best interest of Japan to cease fighting. Had America invaded, the Japanese would have kept on fighting unless given the order to stop. Not only would many American lives have been lost cleaning out all of the fighting forces, everyone in Japan over thirteen was a part of that fighting force. The Japanese people would have been decimated to a point of no return.
Even after having two nuclear weapons dropped on them, many of the Japanese military were unwilling to surrender, regardless of the Emperors wishes. In fact the night the Emperor was preparing to surrender a military coup was staged. It was only the barest of coincidences that prevented this coup from stopping the surrender. Specifically the American military had started giving up that Japan would surrender at all and decided to bomb the last stores of heating oil in the country (with winter approaching). The flight flew over Tokyo and the city was blacked out, which stymied the coup. Even after the surrender, many Japanese military leaders chose to kill themselves rather than surrender. As the war ended the Japanese were preparing a massive propaganda campaign to rally civilians to resist the expected invasion. It's uplifting theme "one hundred million will die in defense of Emperor and Nation." A little cultural note: Ten thousand is the largest number that can be represented by a single character. It is commonly used to represent an indefinitely large number. One hundred million is ten thousand squared, in other words, all will die. To the last man, woman, and child. Would it have succeeded? Not totally. Japan would not have ceased to exist, not everyone would have had the stomach to sacrifice themselves. But many, many would have. Many did in Okinawa. On top of that, the Japanese military showed it's willingness to make sure civilians had their honor preserved (by killing them) both in Saipan and Okinawa. It is not the least bit unlikely that they would have done the same--more likely more!--on the Japanese home islands. On top of that the naval embargo and the devastation of the Japanese infrastructure would have condemned millions to death by starvation and exposure during the winter.
President Harry S. Truman dropped the bombs on Nagasaki and Hiroshima for one reason: not to end the war with Japan, but to intimidate Stalin, keep him out of the Pacific war, deny him a share of the peace that we were going to impose on Japan. History shows there was probably not one single general officer in that war who approved of it, and they all went public very quickly to denounce their Commander-in-Chief.
When debating the topic of why the US dropped the atomic bombs on Japan, one must first consider the prelude to the decision. Estimates of U.S. casualties to invade the Japanese home islands were expected to be high; this estimate was based on the stiff Japanese resistance encountered on Okinawa. Naturally the primary motivation to drop the weapons was to end the war as quickly as possible. Some evidence suggests that the Japanese were seeking to end the war and other evidence suggests that a significant faction in Japan sought to continue the war. While tensions with the Soviet Union would mount in the coming years, the general euphoria of defeating Germany still had not worn off and the Soviet Union still hadn't invaded Manchuria, so clearly the decision to drop the bomb wasn't primarily motivated by a desire to intimidate the Soviets or to prevent the Soviets from seizing ground in China/Korea. In the end, the only way to judge Truman's decision is to look at the information Truman was presented with. There is no clear evidence to show that Truman knew or had any reason to believe the Japanese were going to surrender, he had witnessed a bloody defense of the home islands and was shown high casualty estimates to invade the Japanese home islands. However, the second atomic weapon was dropped a short time after Hiroshima, after the Soviets had invaded Manchura, at a point in time when Japan was in general turmoil, its premier field army (the Kwantung Army was in full retreat) and at a time when Japan's fascist regime was in its death throes. The decision to drop the second bomb MAY have been premature. However, all things considered, please remember that WWII was a brutal war, it was a long war, it was a war in which armies of all sides freely bombed civilian populations. Without condoning the killing of civilians, please remember that the cities bombed were NOT Tokyo or Osaka; the decision to bomb Hiroshima and Nagasaki shows at least SOME deference for human life within the larger context of the brutality of WWII.
The answer is not that simple but as Americans we can say that it was because they bombed Pearl Harbor, or that we were doing a favor to everyone because an invasion on the mainland would have cost many people their lives, but that is more reasoning than answers. If we look at all the facts we could see that America was bombing the Japanese cities with the same types of bombs that the American and British air-forces used against the Germans. Also we see that the Japanese were losing the war greater than thought, there was an American blockade around the island stopping all food and oil from coming into the country, and as we all know humans can not live without food and the Japanese tanks, aircraft's and ships need oil to run so that would have help reduce the resistance from the Japanese. Now I am not saying that I am upset with dropping the bomb because part of me is and part of me isn't. America was winning the war without a doubt I think we did it because of a few reasons, 1) 2 billion dollars were put into the project and Truman was under pressure from the Senate about if that investment was a good idea, 2) I do believe a large part of it was to get back at the Japanese bombing Pearl Harbor. 3) Everyone but McArthur, leader of the Pacific forces, felt that to many Americans would have died, a matter of fact McArthur said that under 200,000 would die and the two bombs kill over that amount when dropped so decide for yourself about that. 4) USSR had probably a bigger influence on the decision that hoped because US was afraid that if USSR took China and some of Japan communism would spread. I am glad that the US did not invade Japan because no matter what the number is I do not want Americans to die, but Japan was losing badly and if we just waited longer Japan would have surrender as long as they could continue to keep their Emperor, which the peace treaty said. I just feel that the US acted to quickly in the decision to drop the Atomic Bombs.
Because Japan would not put an end to the war. They had convinced every citizen to fight to the death using sticks, pitchforks and even rocks to keep away an invading force. Japan had attempted to take over the pacific, killing anyone who got in their way, bombed U.S. interests in Hawaii and boasted of their racial purity that could surely defeat the mongrels of the United States. They refused to surrender because they still believed that they could force better terms of surrender if they held out longer. They believed that they could kill over a million U.S. troops if we attempted to invade the Japanese mainland. Estimates varied greatly depending on who ran the numbers. There was no question that Japan could not be allowed to maintain their military so that they could rebuild just to go after the Pacific again. The Allies had just seen a similar mistake that resulted in the German invasion of Europe and the Allies vowed to not let that happen again. Unconditional surrender was demanded and Japan would not surrender, even after their cities burned and hundreds of thousands died from conventional bombing. Nuclear devices had just been created that were capable of causing unimaginable damage to life and property. Imagine what would have happened back home if the citizens found out that we had a device that could have stopped the war and the President didn't use it and instead almost a million troops were killed in an invasion attempt. Imagine if one of the dead had been YOUR relative, would you be very tolerant that the President didn't use the new weapon? It was an impossible decision. There was no right answer, just the least of two wrong answers.
So they wouldn't have to invade mainland Japan-The US dropped the Atom Bomb on Hiroshima after the sneak attack on Pearl Harbor during WWII. It was the first Atom Bomb to ever be used, and was not the last. The second Atom Bomb was dropped on Nagasaki which was the final straw in ending WWII this day is called V-J Day(Victory over Japan Day).
It was dropped to send a message to the forces that opposed or would oppose the west that the allies had atomic capability. It certainly convinced the Japanese to surrender, though there is some controversy as to the necessity for the dropping of the second bomb.
