It looks like a fake. The use of the language is almost like kanbun, or classical Chinese language. There is a complete lack of hiragana on the flag. There are various names scattered around the periphery, but they look like random names without any context to the supposed recipient. The supposed recipient has a very unlikely last name 壮柴 (Sōshiba?). The recipient's full name is supposed to be Kazuo Sōshiba. I hope you haven't paid good money for this.