Atomic attacks and Soviet entry break Japan's remaining options

Japan's hardliners viewed the war as a struggle for cultural and national survival, while opponents of continued fighting remained divided. In this interpretation, the atomic bombings gave the emperor and Mitsumasa Yonai the catalyst to unite those factions against the hardliners. Soviet entry added a second shock and occupied Japanese forces in Korea and Manchuria, preventing their return to defend the home islands. The alternative was continued conventional bombing, blockade and invasion, with severe consequences for civilians. British planning in the 1930s had already contemplated destroying Japan's fleet and starving the country through blockade, including attacks on fishing vessels. Weak internal transport and dependence on maritime food supplies made Japan particularly vulnerable. Whether another catalyst could have produced surrender remains uncertain.