Factories, schools, neighborhood associations, etc... would present a flag like this to one of their colleagues as he left for war. They would have been given away any time from when the war in China started in the late 1930s, to the end of WW2. Yours looks like it was presented to a Mr. Endō, but I can't make out the first name. Endō Take-something. 遠藤武？. If you send a clearer picture of the lower left corner (see the attached) we might be able to make it out. Also, there is a group in Japan that tries to reunite these flags with the families of the soldiers to whom the flags originally belonged. I think it is called the Obon Society. May be of interest to you to search around for it.