| >...had Russia not also invaded from the North with 1.5 million troops, there's a chance they would not have surrendered The Japanese had already moved all of their experienced troops from Manchuria before the Soviet invasion. They were maybe surprised that the USSR would break the Soviet–Japanese Neutrality Pact, but the defense of the home islands was their main concern at that point. The Japanese knew the USSR was not a threat to the main islands as the Soviets could never have done a large invasion of Japan. The Soviets had a few ships that the USA had given them as part of Project Hula, but that is nothing compared to what would be needed for a full scale invasion of Japan. The Soviets did have plans to possibly attack Hokkaido, but as the wikipedia entry says "...Historians have generally considered it unlikely that an invasion of Hokkaido would have succeeded. " https://en.wikipedia.org/wiki/Proposed_Soviet_invasion_of_Ho... In comparison, the proposed allied invasion was planned to have 42 aircraft carriers, 24 battleships, and 400 destroyers and destroyer escorts. Even that wasn't considered enough: >...Ken Nichols, the District Engineer of the Manhattan Engineer District, wrote that at the beginning of August 1945, "[p]lanning for the invasion of the main Japanese home islands had reached its final stages, and if the landings actually took place, we might supply about fifteen atomic bombs to support the troops." https://en.wikipedia.org/wiki/Operation_Downfall |