On 25 July 1914, the Austro-Hungarian Ambassador to Japan, Baron Ladislaus Müller von Szentgyörgy, wrote a coded telegram to the Austro-Hungarian Minister of Foreign Affairs, Leopold Count Berchtold. In his telegram, Müller describes the Japanese Minister of Foreign Affairs’ reaction to the 28 June 1914 Sarajevo murder of Archduke Franz Ferdinand.
Baron von Müller to Count Berchtold. Tokyo, 25 July 1914.
Ultimatum to Servia.
Received your Excellency’s telegram.
According to instructions, immediately made communication to [the] Imperial [Japanese] government. [The] Minister of Foreign Affairs expressed his thanks and asked, if I knew whether anyone would back up Servia. I answered that it was well known that during latter years Servia had had several patrons; in this case, if my information was correct, it is only Servia alone. The Minister was much interested in the details of the murder of Sarajevo [of Archduke Franz Ferdinand], the success of which, after the many previous unsuccessful attempts, was to him incomprehensible.
With regards to the concluding words of the telegram, I must say that I did not think it politically wise to call the Tokyo government’s attention to the favourable opportunity offered just now, because [of Japan’s] alliance with England, the good relations with Russia, and a general tendency to befriend the Entente, do not tally with any such plans as those alluded to in the telegram. I will telegraph on military matters when I have spoken to the [Austro-Hungarian] military attaché, who has already received notice to start for home.
If the opportunity occurs, I will remember the secret telegraphic instructions of 30 November 1912.
Source: 1919 Austro-Hungarian Red Book, with minor edits.