The Soviet–Japanese War (; ), known in Mongolia as the Liberation War of 1945 (), was a military conflict within the Second World War beginning soon after midnight on 9 August 1945, with the Soviet invasion of the Japanese puppet state of Manchukuo. The Soviets and Mongolians ended Japanese control of Manchukuo, Mengjiang (Inner Mongolia), northern Korea, Karafuto (South Sakhalin), and the Chishima Islands (Kuril Islands). The defeat of Japan's Kwantung Army helped bring about the Japanese surrender and the termination of World War II. The Soviet entry into the war was a significant factor in the Japanese government's decision to surrender unconditionally, as it was made apparent that the Soviet Union was not willing to act as a third party in negotiating an end to hostilities on conditional terms. Summary At the Tehran Conference in November 1943, Joseph Stalin agreed that the Soviet Union would enter the war against Japan once Germany was defeated. At the Yalta Conference in February 1945, Stalin agreed to Allied pleas to enter World War II in the Pacific Theater within three months of the end of the war in Europe. On 26 July, the US, the UK, and China made the Potsdam Declaration, an ultimatum calling for the Japanese surrender that if ignored would lead to their "prompt and utter destruction". The commencement of the invasion fell between the US atomic bombings of Hiroshima on 6 August and Nagasaki on 9 August. Although Stalin had been told virtually nothing of the US and UK's atomic bomb program by Allied governments, the date of the invasion was foreshadowed by the Yalta agreement, the date of the German surrender, and the fact that, on 3 August, Marshal Vasilevsky reported to Stalin that, if necessary, he could attack on the morning of 5 August. The timing was well-planned and enabled the Soviet Union to enter the Pacific Theater on the side of the Allies, as previously agreed, before the war's end. The invasion of the second largest Japanese island of Hokkaido was originally planned by the Soviets to be part of the territory taken. At 11 pm Trans-Baikal time on 8 August 1945, Soviet foreign minister Vyacheslav Molotov informed Japanese ambassador Naotake Satō that the Soviet Union had declared war on Japan, and that from 9 August the Soviet Government would consider itself to be at war with Japan. At one minute past midnight Trans-Baikal time