On February 4–11, 1945 (the 20th year of the Showa Era), the leaders of the United States, Britain and the Soviet Union met in Yalta on the Crimean Peninsula and secretly decided that the Soviets would join the war against Japan a few months after Germany’s unconditional surrender. As Japan’s defeat seemed inevitable, Prime Minister Kantaro Suzuki’s Cabinet, which was inaugurated in April 1945, desperately moved to seek Moscow’s mediation to help reach a peace agreement to bring the war to a close.
 These hopes were dashed when the United States successfully conducted its first atomic bomb test, while the Soviet Union was seeking an opening to join the war against Japan.
 Why could Japan not prevent the United States from dropping the atomic bombs on Japan and stop the Soviet Union from entering the war?

Big Three make a secret agreement

 On February 4, 1945, U.S. President Franklin D. Roosevelt, British Prime Minister Winston Churchill and Soviet Premier Josef Stalin met at Yalta on the Crimean Peninsula in the southern Soviet Union, now Ukraine.

 Stalin chose Yalta as the venue, a distant location that forced his counter­parts to make a long, grueling journey. Roosevelt, who was sick at that time, had to travel by ship, transfer to an airplane and then be driven by car to get to his destination. It was snowing when he arrived.

 Roosevelt and Churchill stayed at a palace built in the days of Tsarist Russia. The palace was heavily bugged by the Soviet security police. According to records, Sarah Churchill, who accompanied her father on the trip, privately told him that lemon would go nicely with caviar. They woke up the next day to find a lemon tree had been planted in an orange orchard within the palace.

 At this first meeting since the Tehran Conference in November 1943, the leaders discussed how to handle Europe’s postwar reorganization. They signed the Yalta Agreement, which declared Germany would be temporarily split into four zones of occupation controlled by the United States, Britain, France and the Soviet Union, settled the postwar borders of Poland and allowed the Soviet Union to occupy the Baltic countries of Latvia, Estonia and Lithuania to remain under the Soviet sphere of influence.

 The three leaders also secretly agreed that the Soviet Union would join the fight against Japan two or three months after Germany fell, an idea agreed to by Roosevelt and Stalin beforehand.

 Roosevelt put the secret agreement in his private safe. China was a member of the Allied Powers but was not informed of the agreement’s content. U.S. President Harry Truman, who succeeded Roosevelt who died two months after the conference, wrote in his memoir that he did not know what was written in the document until he opened Roosevelt’s safe.

 Made public by the United States after the war, the secret agreement stipulated three conditions for Soviet participation in the fight against Japan:

 Roosevelt accepted these conditions demanded by Stalin concerning Japan. Before their meeting, Roosevelt told Stalin in a written document that he approved of Japan’s returning Sakhalin and the Kurils to the USSR.

 Based on these agreements, after the war the Soviet Union obtained part of East Prussia, which included Konigsberg (now Kaliningrad), established satellite states in Central and Eastern Europe and took over all of Sakhalin and the Kurils as well as four northern islands—Kunashiri, Etorofu, Habomai and Shikotan located south of the Kurils. The four islands off eastern Hokkaido are historically Japan’s territories, known as the Northern Territories.

 As the Cold War started to tighten its icy grip on diplomatic relations, the Yalta Agreement was branded by Poland and other Soviet satellite states in Eastern Europe as a “betrayal” that had brought them under communist control owing to Roosevelt’s concessions to Stalin. This condemnation is still heard today, more than a decade after the Soviet-Eastern Europe bloc collapsed.

 “The captivity of millions in Central and Eastern Europe will be remembered as one of the greatest wrongs of history,”U.S. President George W. Bush said in his speech in Riga, Latvia, on May 7, 2005.

 Why did Roosevelt make so many concessions to Stalin?

 It has often been pointed out that Roosevelt thought at the time of the Yalta Conference it was necessary to ensure the Soviets would join the war against Japan to bring a speedy end to the fighting. With appalling casualties expected during the planned landing on the Japanese mainland by U.S. forces, it was essential to have the Kwantung Army, the Imperial Japanese Army’s elite unit, kept busy fighting in Manchuria.

 According to U.S. Ambassador to the Soviet Union W. Averell Harriman, giving Moscow the Kuril Islands was a small matter to Roosevelt compared with the huge advantage to be gained by Russian help in defeating Japan.

 Some observers speculate that Roosevelt’s poor health impaired his judgment, while his camaraderie with Stalin and his administration’s pro-Soviet stance also played a part in preventing Roosevelt from detecting the true Soviet ambitions for the postwar order. According to documents made public recently in the United States on Soviet code-breaking operations before and after the war, part of the reason for this pro-Soviet stance was that a then U.S. deputy assistant treasury secretary and others in the administration were actually Soviet spies.

 At the time of the Yalta Conference, Churchill’s doctor described Roosevelt as being seriously ill and said his cognitive ability was waning.

 At the Tehran Conference, Roosevelt called Stalin “Uncle Joe,” and after the conference, he said his Soviet counterpart was a man who “combines a tremendous, relentless determination with stalwart good humor.”

 According to former U.S. Secretary of State Henry Kissinger, Churchill wanted to reconstruct the traditional balance of power in Europe while Stalin “strove to cash in on” his country’s victory in expanding its influence in Central Europe. For his part, Roosevelt “envisioned a postwar order in which the three victors, along with China, would act as a worldwide board of directors of the world, enforcing the peace against any potential miscreant.”