These wonderful vintage porcelain earrings were made by the Japanese company Toshikane of Arita in northern Japan. They are in the form of a Noh mask depicting an old man. The company made very high quality porcelain and their items, particularly jewelry are highly collectible. They are screwback earrings and they are marked with a fan mark and I believe the word Japan. The mark is under the screwback mechanism so it is difficult to read.
They measure about 7/8 inch by 1/2 inch and they are in excellent condition.