Never saw that flag before. You might try posting on a forum called "Warrelics" under the Japanese militaria sub forum.
The symbol inside the cap just says 中 (chū - means middle, and in this case it means "regular size")
The emblem on the cap might be some arsenal mark, or maybe even a corporate mark (from a company working for the military, like a railroad or something).
Sorry I can't be of more help.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.