What is the main theme of the letter?

A check of the letter's date, 1 May, 1930, against a chronological table showed that it was written shortly after the signing of the London Naval Treaty on 22 April. At that juncture, fierce internal conflicts were being waged within both the Navy and the Imperial Diet over the ratification that the Treaty required after its signing. "Ratification" was the final expression of the will of a nation for concluding a treaty.

What was the London Naval Treaty?

It was an international treaty to restrict the number of auxiliary vessels of the navies involved in the negotiations. In April 1930 (Showa 5), the HAMAGUCHI Osachi Cabinet forced through the ratification of the Treaty, fending off opposition from the Chief of the Navy General Staff. This was regarded as a "violation" of the Supreme Command of the Emperor who as the supreme commander of the armed forces had the power to decide on the military's operational requirements. The result was a major crisis.

We can surmise from the latter half of the letter that the main theme probably was that: TAKARABE, having returned from the London Naval Conference, finds himself in a complicated position, and needs a confidante with whom to consult about the problem.

Figure: Diagram of the various factions favoring/opposing the conclusion of the London Naval Treaty.