My family is full of combat veterans from all branches of service that reaches back to the birth of the U.S., with legacies rooted both in Europe and Native America before that time, as well.
Many relatives never spoke of their combat experiences and it was only after speaking to family friends (who were also former military) after their passing that some of their battles were revealed.
In regards to your Yosegaki Hinomaru, I am sure that the Obon Society would be able to provide interpretation and a possible time period that it was presented to the Japanese soldier, they have considerable resources for identifying such items.