The following translation from our “Prelude to Pearl Harbor” series is from a Top Secret letter consolidating information from a series of Tokyo cipher telegrams on how potential actions against England and the USA would depend on a non-aggression pact between Japan and the USSR. The letter, sent from an unnamed Soviet agent in Tokyo, was dated 24 April 1941. This account of coded intelligence reports sent from Tokyo covers February and March 1941.
There are a number of curiosities associated with this letter worth noting. First, it appears to be a rambling recap of intelligence information with which the recipient is already familiar – note the brevity. The topics jump from the coming neutrality pact between the Soviets and the Japanese (and the need to accelerate its signing) to the confirmation of the “illness” of Prince Chichibu, who the previous year had been diagnosed with tuberculosis. The use of quotation marks might suggest that the author may still have doubts regarding the veracity of the diagnosis, given that it allowed the Prince to retire from active duty in order to convalesce. Perhaps the author felt that this was a convenient way to keep Chichibu out of the war? Finally, the author’s intimation in the last paragraph that his source’s intelligence is of poor quality. There is a good deal of information absent that may only have been known to the addressee and the agent.
March 1941
1. For the movement to the south into Indochina, there are two divisions of Japanese troops available; two other divisions are located in Formosa and on Hainan Island.
2. The concentration of more than 50,000 British troops in the Strait of Malacca has extremely agitated the Japanese higher headquarters, which is urgently considering the possibility of dispatching a larger contingent of troops to the south.
3. Any actions against England or the US will depend on the non-aggression pact with the USSR, the signing of which is to be accelerated.
Matsuoka and Shiratori intend to travel to Moscow, although it is possible that Shiratori will only go for preliminary discussions. If a corresponding non-aggression pact will carry fundamental importance for the movement into Singapore and the Dutch East Indies, then in that case, it is possible that only Matsuoka himself will travel to Moscow.
The technical committees for the tripartite pact are still not ready.
Chichibu’s “illness” is confirmed.
Sent second classified letter, distributed in Japan against Konoe.
The circumstances surrounding our meeting did not allow us to ask him questions about the low quality of his information. We will do this in the coming days.
Translation © 2025 by Michael Estes and TranslatingHistory.org
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