Truman was desperately anxious to get Japan— or at least "the Japanese armed forces"—
to surrender unconditionally before Russia entered the war. They may have suspected this at the time, on the strength of the American broadcasts to that effect, which began as early as May 8 [Much is made of these in the Soviet History. (IVOVSS, vol. V, p. 536)], but consoled themselves with the thought that Japan could not be defeated—at least not within a short time—without the Russians smashing the Kwantung Army in Manchuria.
They had understood from Roosevelt at Yalta that, without Russian participation, the war against Japan would have to go on till 1947, and would cost the Americans and British at least another million men.
As early as February-March, the Japanese sought Russian mediation in their desire to end the war with the USA and Britain. The Soviet History enumerates several such peace-feelers:
First of all, two "private" persons approached the Russians on behalf of the Japanese Government—Mr Mijakawa, the Japanese Consul-General in Harbin and
Mr Tanakamaru, a fishing magnate.
On March 4, the same Tanakamaru called on Mr J. Malik, the Soviet Ambassador
in Tokyo, saying that neither Japan nor the United States could start speaking of peace. A "divine outside force" was necessary to bring about a peace settlement, and the Soviet Union could play that rôle.
After the formation of the Suzuki Government, these peace-feelers became even
more explicit. Foreign Minister Togo asked Mr Malik on April 20 to arrange for
him a meeting with Mr Molotov.
Still anxious to avoid unconditional surrender to the USA, Togo sent ex-premier
Hirotake Hirota to see Malik on June 3. He stressed Japan's desire to improve her relations with the USSR. A second meeting took place on the following day, and two further meetings on June 24.
[IVOVSS, vol. V, pp. 536-7.]
The History dismisses all these Hirota visits to Malik and his offers of large-scale Soviet-Japanese economic co-operation as "a piece of effrontery coming from a gang guilty of so many treacherous acts towards the Soviet Union"; but the fact remains that Malik consented to see Hirota four times.
Nevertheless, the Hirota mission failed, and the Japanese Government now tried to
establish direct contact with the Soviet Government in Moscow. The Emperor decided to send Prince Konoye to Moscow on July 12, and Mr Sato, the Japanese Ambassador in
Moscow was instructed to inform the Soviet Government of the Emperor's desire. But in vain. In the words of the History:
This Japanese proposal was left without an answer by the Soviet Government which
was, moreover, preparing to go to the Big-Three Conference at Potsdam. Here the
Soviet delegation fully informed its allies of these Japanese "peace" moves. Thus, the Japanese imperialists' attempts to split the Allies failed completely.
[IVOVSS, vol. V, p. 538.]
At Potsdam the American military wanted to know when exactly the Russians would
attack in the Far East. The Soviet Chief of Staff, General Antonov confirmed that all would be ready by August 8, but much depended on the outcome of the Soviet-Chinese
talks which had begun in Moscow shortly before the Potsdam Conference.
As we now know, the Americans were, in fact, no longer interested at the time of
Potsdam in Russian participation in the war against Japan. Churchill tells with
undisguised glee how he and Harry Truman fooled Stalin.
As Churchill tells the story:
On July 17 (at Potsdam) world-shaking news arrived... "It means", Stimson said,
"that the experiment in the Mexican desert has come off. The atomic bomb is a reality".
And almost the first thought that occurred to Churchill was that the Russians could be dispensed with in the war against Japan:
We should not need the Russians. The end of the Japanese war no longer depended
on the pouring in of their armies... We had no need to ask favours of them... I
minuted to Mr Eden: " It is quite clear that the United States do not at the present time desire Russian participation in the war against Japan."
There was no doubt, he wrote, that the bomb would be used.
A more intricate question was what to tell Stalin. The President and I no longer felt we needed his aid to conquer Japan... In our opinion they (the Soviet troops in the Far East) were not likely to be needed, and Stalin's bargaining power, which he had used with such effect upon the Americans at Yalta, was therefore gone.
And then came Churchill's singularly tortuous mental compromise:
Still, he had been a magnificent ally in the war against Hitler, and we both
(Churchill and Truman) felt that he must be informed of the great New Fact which
now dominated the scene, but not with any particulars.
[Churchill, op. cit., vol. VI, pp. 552-4.]
In the end the procedure chosen was this: Nothing was going to be put in writing. Instead, Truman said:
"I think I had best just tell him after one of our meetings that we have an entirely novel form of bomb, something quite out of the ordinary, which we think will have a decisive effect upon the Japanese will to continue the war."
Churchill agreed with this "procedure".
[Ibid., p. 554.]
And this is how it was done.
On July 24, after our plenary meeting had ended... I saw the President go up to
Stalin, and the two conversed alone, with only their interpreters. I was perhaps five yards away, and I watched with the closest attention their momentous talk. I knew what the President was going to do. What was vital to measure was its effect on
Stalin. I can see it all as if it were yesterday. He seemed to be delighted. A new bomb! Of extraordinary power!... What a bit of luck!... I was sure that he had no idea of the significance of what he was being told... If he had had the slightest idea...
his reactions would have been obvious... Nothing would have been easier than for
him to say:
"... May I send my experts to see your experts tomorrow morning?" But his face remained gay and genial...
"How did it go?" I asked (Truman). "He never asked a question," he replied.
[Churchill, op. cit., vol. VI, pp. 579-80. The suggestion that the Russians already knew all about the bomb from their own intelligence is not borne out by their behaviour after Potsdam.]
I must add here a very important historical point which dots the i's in Churchill's account to an extraordinary degree.
When, in 1946, I privately asked Molotov whether the Soviet Government had been
informed at Potsdam that an atom bomb would be dropped on Japan, he looked startled, thought for a moment, and then said: "It's a tricky subject, and the real answer to your question is both Yes and No. We were told of a 'superbomb', of a bomb 'the like of which had never been seen'; but the word atom was not used."
I often wondered afterwards whether Molotov's answer was strictly true, and I believe it was; had Truman really told Stalin that the new weapon was not just a "super-bomb", but an atom bomb, it is almost inconceivable that Stalin could have registered the news as calmly and cheerfully as Churchill said he did, and done nothing at all about it.