Assumed attribution. See also https://asiamedals.info/threads/japanese-postal-hat-badges.24139/
Symbol 〒 in the center https://asiamedals.info/threads/symbol-of-japanese-post-yubin-maku-and-its-history.24108/
cap badgeofjapanese ministry of communications
cap badgeofjapaneseposthatbadgeofjapanese ministry of communications
hatbadgeofjapanesepostjapanesepostoffice badge
逓信省帽章
逓信省章