Here too are the triangle patches worn on upper arm of HJ uniform, including those at Shanghai. If they had their own Gebietsarmdreieck, it seems more than likely that those in Japan did too.
Did any HJ have to return to Germany with the outbreak of the Pacific war?
Janel90, I am glad to see you are still here and that the Forum has been of further help.
- Here are the instructions how to upload a photo to the Forum from your laptop.
- Jentschura, Hansgeorg; Jung, Dieter; and Mickel, Peter. Warships of the Imperial Japanese Navy 1869-1945 (US Naval Institute Press, 1977; also Lionel Leventhal Ltd, 1977). Originally published as DIe Japanische Kriegschiffe 1869-1945 (J. F. Lehmanns Verlag, 1970).
Whether Wenneker or any other officer in this post, the German naval attaché in Tokyo would have been concerned with things like the support of U-boat operations in the Indian Ocean, the rising losses of German auxiliary cruisers and blockade runners, and the start of I-boat and U-boat transport missions to replace the latter.The idea for [this book] was that of Erich Gröner, historian of the German Navy ...
In October 1942, thanks to a special request by Hitler, the German Naval Attaché in Tokyo, Admiral Wenneker, was permitted to pay a short visit of inspection to a Yamato-class super-dreadnought in a dockyard, and then to cable a very detailed description of the ship to Berlin. On 22nd August 1943, Gröner was shown this report at the Führer HQ for the purpose of interpretation and preparation of a design sketch drawing, under security supervision. Later, at the time of the collapse of the Third Reich, he rescued a copy of this sketch intending to use it as the frontispiece of a volume on Japanese warships. Gröner embarked on an enthusiastic exchange of material with Shizuo Fukui, a Japanese naval constructor who planed similar publications in Japan ... [and so the foundation for this book began with] the information forwarded to Gröner by Fukui in the 1950s ...
He did not know of course, that his communications cipher had been broken by the Americans. It would be interesting to know what if anything they learned about Yamato from here.
If Jentschura et al are correct, It took almost eleven months for the Führer’s request to be answered.
Combinedfleet.com’s tabular record of movement for Yamato dates Admiral Wenneker’s visit to that battleship as 1943, when she was drydocked at Kure:
The Admiral’s wear of Japanese Navy uniform is the only German example of this I know of. Wearing their own uniform is often a courtesy many armed forces allow their foreign allies for certain needs. Could there have been Japanese attachés with the Germans in Europe, for whom the same might have been done?16 July 1943:
YAMATO is visited by the German Naval Attaché to Tokyo, Konteradmiral (later Admiral/Ritterkreuz) Paul Wenneker. Prior to Wenneker’s arrival there are a series of debates between Vice Admiral (later Admiral) Nomura Naokuni (former CO of KAGA), CO of the Kure Naval Base, and Rear Admiral Matsuda, YAMATO's CO, concerning security issues. 
The officers are of different opinions as to Wenneker’s ability to distinguish between large-caliber guns. A data sheet is given to the German prior to his visit that describes YAMATO's main armament caliber as 40 cm, rather than the actual 46 cm. Nomura thinks that the German Admiral, a former CO of the 28.3-cm gun Panzerschiff DEUTSCHLAND/LÜTZOW, will not be able to tell the difference between 40 and 46 cm. guns, but Matsuda is not so sure and opposes the visit.
Wenneker is invited to spend a night at the Kure Navy Club. He dons an IJN uniform. His stay aboard YAMATO the next day is fairly short and the route chosen avoids the main gun turrets. The tour is less than one hour and areas below deck are not shown at all. Wenneker admires the elevator, bridge, air defense center and the main gun director. The German attaché even starts a discussion about the best location for battleship reserve main gun directors with Matsuda.
It might be said that German surface power at sea was waning at this time while that of the Japanese had been stopped from rising. But that would not have been known, either to Admiral Wenneker or, indeed, to his Japanese hosts.
What Germans in Japan had heard about the course of the war –- in both Europe and Pacific -- might also be an interesting perspective, although a general one.
Janel, you might consider –- if you think it is appropriate –- adding in your mother’s book an acknowledgment to the Axis History Forum, among the many others. If he agrees to it, Hisashi is the only one who might be named there among those of AHF, because his was the most important information in this thread. As a research forum, we have been pleased to assist many writers.