Many commentaries, focused on the use of atomic weapons, suggest that use of such weapons of mass destruction was not necessary given that Japan was attempting to open peace negotiations via the Soviets as intermediaries. As noted in earlier posts, if one wishes to assert that peace negotiations via the Soviets was a viable pathway, one needs to account for the history of Japanese-Soviet relations which in general had always been contentious. Military actions include the 1903-1905 Japanese-Soviet war which concluded with a resounding Japanese victory at the naval battle of Tsushima, the 1939 Japanese invasion (unsuccessful) of Soviet-held Mongolia, and a long history of border conflict in northern Manchuria and Siberia.

The 1939 German–Soviet Non-Aggression Pact surprised Japan. Berlin, its nominal Axis partner, had essentially made peace with Moscow just as Japan had been fighting the Soviets. This left Tokyo diplomatically exposed. With tensions high, both Japan and the USSR had reasons to avoid a two-front war. The Soviets feared German aggression. By securing peace with Japan in the east, he could concentrate forces in the west. A neutrality pact would allow Japan to focus on expansion southward (toward Indochina, the Dutch East Indies, the Philippines) without worrying about Siberia. The pact was signed on April 13, 1941. Both sides pledged to respect each other’s territorial integrity and neutrality if either was attacked by a third power. On April 5, 1945 the Soviets informed Japan that they would not renew the pact in April 1946. But on the same day, the Soviets began deploying approximately 1 million soldiers to the Far East in fulfillment of a 1943 pledge to the Allies to enter the Asia-Pacific war within 3 months of the surrender of Germany. 

Trying to enlist the Soviets as brokers to start negotiations with the Allies was a fool’s errand. For historians to continue the argument had some merit before 1995, but not afterwards when the treasure trove of historical information was declassified. It is hard to sustain the argument that there was a chance the Soviets would be honest brokers. The Soviet intent was clear. They intended to achieve in 1945 what they had failed to achieve in 1905 – warm water ports in the Pacific. The shortest route to that goal was the promised war on Japan.

Nonetheless, the Japanese were indeed attempting to use the Soviets to negotiate an end to the war on terms more favorable than unconditional surrender. 

By the summer of 1945, as the Supreme Council remained deeply committed to Ketsu-Go, the final decisive battle, the unofficial “peace faction” wanted to explore a way to end the war. The initial inquiry into Soviet assistance was undertaken by Foreign Minister Shigenore Tōgō with the Soviet ambassador in Tokyo, Jacob Malik. Tōgō was given the signal to pursue this avenue after a July 11 conversation between Lord Privy Seal Kido and Emperor Hirohito. In the conversation, Kido records that the Emperor wanted peace “through the good offices of the Soviet Union.” The next day Foreign Minister Tōgō instructed Ambassador Naotake Satō in Moscow to approach Soviet leaders to request Soviet mediation. The instructions to Satō, a career diplomat with extensive experience in European diplomacy. The same day Tōgō instructed Kōki Hirota to make a parallel inquiry via Malik in Tokyo. Hirota received a non-commital response with a promise to forward the idea to Moscow. Over the next few days, Hirota again met with Malik, who consistently delayed or gave evasive replies.

In Moscow, Satō’s instructions from Tōgō were to request Soviet mediation to end the war, but with the condition of not accepting the terms of unconditional surrender. In the July 13 cable, no other instructions or directions were given. The next day Satō met with Soviet Deputy Foreign Minister Lozovsky, delivered the emperor’s request, and as instructed proposed sending a special peace envoy, Prince Konoe, to speak with Foreign Minister Vyacheslav Molotov who was attending the Potsdam Conference.  Five days later, July 18, Lozovsky responded in writing that the Soviet government cannot give a specific answer because the proposal was too general.  Satō reported back to Tokyo (Tōgō) that the Soviets were clearly delaying and that they were unlikely to engage unless Japan at least offered some “terms” that would be that starting position. 

All the while the Allies are reading the diplomatic traffic via MAGIC, often reading Satō’s messages to Tōgō before he did. The exchanges are clear evidence that Tōgō is constrained by the position of the Supreme Council and the Emperor’s vague direction (leading to no initial terms) and the Satō is frustrated in that he has nothing to work with and the Soviets are sending signals the endeavor is a low priority if it is a priority at all. Then on July 26, the Potsdam Declaration was issued calling for Japan’s unconditional surrender.

At this point, Satō’s message to Tōgō is that the only possible avenue left is to propose the acceptance of unconditional surrender with one proviso: integrity of the kokutai of the nation – the Emperor and Imperial House remain in place. Tōgō responded he cannot authorize Satō to offer those terms. At this point, Satō has not met with Molotov, there is more delay from Soviet spokesmen in Tokyo and Moscow, there is nothing substantive to report

Soviet Foreign Minister Molotov finally met with Satō to deliver a message—but it was the Soviet Union’s declaration of war against Japan, effective the following day, August 8 – two days after the bombing of Hiroshima.

One is left to wonder why “they” would not entertain Satō’s proposal of the one-condition acceptance of unconditional surrender. But then you have to ask who is “they.” It is the Supreme War Council and the Emperor. They were still committed to Ketsu-Go and the dynamics of the inner workings of the Council. Japan was defeated but had not reached the political decision to surrender.

At the end, Satō’s proposal was essentially the terms of surrender announced by Emperor Hirohito on August 15 and signed aboard the USS Missouri on September 2, 1945. 

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Image credit: various photographs from Naval Aviation Museum, National World War II Museum, and US Navy Archives.