What Really Ended World War II: The Atomic Bomb or the Soviets?

Japan’s surrender in August 1945 followed several shocks in rapid succession. The United States bombed Hiroshima on 6 August and Nagasaki on 9 August. Between those attacks, the Soviet Union declared war on Japan and launched its offensive in Manchuria, ending Tokyo’s hope of using Moscow as a diplomatic intermediary. This short documentary asks how those events affected a divided Japanese leadership. The question cannot be settled by treating the atomic bombings, Soviet intervention and the emperor’s decision as isolated developments. They unfolded within an already disastrous military situation and a debate over the terms on which the war might end. Diplomatic documents and contemporary records reveal the pressure on decision-makers, while historians differ over the relative weight of each factor. The explanation here keeps that debate open. It follows the sequence of events without replacing a complicated surrender with a single inevitable cause. Music: Historium Soundtrack Library Sources and further reading: The Atomic Bombings of Japan and the End of World War II, 80 Years Later https://nsarchive.gwu.edu/briefing-book/nuclear-vault/2025-08-05/atomic-bombings-japan-and-end-world-war-ii-80-years-later The Japanese Ambassador in the Soviet Union to the Japanese Minister of Foreign Affairs, July 12, 1945 https://history.state.gov/historicaldocuments/frus1945Berlinv01/d584 The Surrender of Japan: Japanese Government Account and Imperial Conferences https://history.state.gov/historicaldocuments/frus1945v06/d488 Invasion of Manchuria https://www.trumanlibrary.gov/education/presidential-inquiries/invasion-manchuria