A few technical difficulties this end...can't seen to post zipped files and server won't let me upload them as they are too large when unzipped - despite being taken on email compatible camera format. Will endeavour to rectify...
That is excellent, thank you Toritoribe. That matches exactly the story I was told by the person I bought it from that it came from a Japanese Warship at the end of World War 2. The box contains an electrical multi-meter which I have been able to date to July 1941.
The three characters underneath the five you refer to are quite hard to read. I think I will carefully try to clean them, or perhaps draw them and post another photograph. I really appreciate your help with this as it is a fascinating story.
I've tried to draw what I can see (please don't laugh!) but there is quite a lot of varnish on top of the inscription, and there are scratches in the varnish which may have removed some of the original paint.
If my drawing is not very helpful, I will try to carefully remove the varnish.
That's brilliant Toritoribe. That all makes sense with the context. Forgive me for not originally giving you the background to the story. I didn't want to 'lead' your interpretation of the text.
The full story is as follows...
I bought the multi-meter from a lady who told me that her father had been a Leading Radio Mechanic for the Special Boat Section at the end of WW2. As an electrician, he was one of those given the task of removing the radar capability from Japanese Warships stationed in Surabaya, Java. The commanding officer gave him the boxed meter as a token of friendship, complete with the inscription and his initials 'RW' painted on the lid. The gentleman has recently passed away, aged 91.
I hope, like me, you have found this story interesting, and I thank you for your patience and immeasurable assistance in solving the mystery.
If I can ever be of assistance, please do not hesitate to let me know...I have added a photo of the meter just to complete the story.
電波探信儀 means "radar", so I thought 探信儀室 would refer to "radar room", but 探信儀 without 電波 is "active sonar", so 探信儀室用 should be translated as "for active sonar room" in this case.
What is written at the bottom of the meter is 九八式無線機器試験器甲 Type-98 radio equipment tester first type, thus, it's a circuit tester used in an active sonar room of a warship.
Thanks for the update, I wouldn't be surprised if the sonar and radar equipment was all located in the same place onboard a warship. I was hoping that the inscription might refer to a specific ship, but I'm really pleased with all the information you have provided as it ties in perfectly with the story I was given.
Thanks again for all your help.