皇太子殿下御降誕紀念牌

See also https://asiamedals.info/threads/birth-of-his-imperial-highness-the-crown-prince-celebration-society-commemorative-paperweight.26749/ Officially these medals were called paperweights. Article published in Asahi Shimbun on December 29, 1933 / Morning edition, page 11, column/...