Explain the reasons for the defeat of Japan by 1945, including the American advance and the decision to drop the atomic bombs

What this dot point is asking

SEAB wants you to explain why Japan was defeated by 1945 and why the United States chose to drop atomic bombs on Hiroshima and Nagasaki to end the war. You should be able to explain the turning of the tide in the Pacific (the Battle of Midway, the island-hopping strategy and the naval blockade), the reasons for the decision to use the atomic bombs, and the debate over that decision. The task combines explanation of Japan's military defeat with explanation and some judgement about the controversial decision to use the bombs. A strong answer on the bombs presents the main reason clearly and shows awareness of the debate.

The answer

The turning point: Midway

Japan's run of conquests was halted in 1942. The key turning point at sea was the Battle of Midway in June 1942, where the United States navy, partly through breaking Japanese codes, sank several Japanese aircraft carriers in a single battle. This was a disaster Japan could not replace, because the United States could build new carriers far faster than Japan. After Midway, the initiative in the Pacific passed to the Americans, and Japan was increasingly on the defensive. The vast industrial power of the United States, the same factor that helped defeat Germany, now began to tell against Japan.

Island-hopping and the blockade

The United States adopted a strategy known as "island-hopping". Rather than capturing every Japanese-held island, the Americans seized key islands and used them as stepping-stones and air bases to advance steadily toward Japan, bypassing and cutting off others. The fighting was often ferocious, as Japanese forces resisted fiercely. At the same time, American submarines and ships blockaded Japan, sinking its merchant ships and cutting off the imports of oil, food and raw materials on which Japan depended. As the Americans drew closer, they also began heavy bombing of Japanese cities. By 1945 Japan was being strangled and battered, its position hopeless, yet it had still not surrendered.

Why Japan kept fighting

Even as defeat became certain, Japan fought on, which is important for understanding the decision to use the atomic bombs. Japanese military culture placed great value on fighting to the end rather than surrendering, and the defence of islands close to Japan, such as Okinawa, had been extremely bloody for both sides. American leaders looked ahead to invading the Japanese home islands and feared it would cost a huge number of lives, both American and Japanese, given how fiercely the Japanese were likely to resist. This fear shaped what came next.

The atomic bombs, August 1945

By 1945 the United States had secretly developed a new and devastating weapon, the atomic bomb. After Japan ignored a demand to surrender, the United States dropped an atomic bomb on the city of Hiroshima on 6 August 1945, killing tens of thousands of people instantly and destroying much of the city. When Japan still did not surrender, a second atomic bomb was dropped on Nagasaki on 9 August 1945. Around the same time, the Soviet Union declared war on Japan and invaded Japanese-held territory. Faced with this overwhelming pressure, Japan finally surrendered in August 1945. The Second World War was over.

The debate over the bombs

The decision to use the atomic bombs is one of the most debated in history, and the syllabus expects you to be aware of the arguments. Those who defend it argue that the bombs forced a quick surrender, avoided an invasion of Japan that could have cost enormous numbers of lives on both sides, and so actually saved lives overall. Critics argue that Japan was already almost defeated and might have surrendered soon anyway, that the huge loss of civilian life was unjustified, and that other motives, such as demonstrating American power to the Soviet Union, may have played a part. A good answer recognises that the main stated reason was to end the war quickly and avoid a costly invasion, while acknowledging that the decision remains controversial.

Examples in context

Example 1. The cost of Okinawa. The battle for the island of Okinawa in 1945 was extremely bloody, with very heavy casualties on both sides and among civilians, as Japanese forces resisted to the end. American leaders looked at Okinawa and concluded that invading Japan itself would be even more costly. This example is central to the main argument for using the atomic bombs: the fear that a conventional invasion would cause enormous loss of life.

Example 2. Hiroshima and the dawn of the nuclear age. The atomic bomb dropped on Hiroshima on 6 August 1945 destroyed most of the city and killed tens of thousands of people instantly, with many more dying later from injuries and radiation. Beyond ending the war, it marked the beginning of the nuclear age, in which such weapons would dominate the coming Cold War. This links Japan's defeat to the arms race and the threat of nuclear war that followed.

Try this

Q1. Which two Japanese cities had atomic bombs dropped on them in 1945? [3 marks]

• Cue. Hiroshima (6 August 1945) and Nagasaki (9 August 1945).

Q2. Explain why the United States used the strategy of "island-hopping" against Japan. [5 marks]

• Cue. Rather than capturing every island, the Americans seized key islands as bases and stepping-stones toward Japan, bypassing others; this saved time and lives while bringing American forces and aircraft closer to Japan.

Q3. "The United States dropped the atomic bombs mainly to save lives by avoiding an invasion of Japan." How far do you agree? [8 marks]

• Cue. Argue this was the main stated reason, supported by the fear after Okinawa, but weigh against the view that Japan was nearly beaten and that other motives (such as influencing the Soviet Union) may have played a part.