Thank you for contacting Mearto. This is a Japanese somayaki cup. Somayaki is also called soma ware, obori ware, or obori soma ware. This kind of pottery features a crackle glaze and green hues, and a distinctive double later with cut-outs. Many artists paint golden horses on the pieces. This is because “ma” in “soma” means horse. There are several different companies that produce this kind of porcelain. It began to be made in the 1600s, and regained popularity in the last quarter of the 20th century. Soma ware like yours is still being produced.
A single somayaki tea cup’s Fair Market Value, based on auction sales, is between $10 and $20.

Soma ware info
https://en.wikipedia.org/wiki/%C5%8Cboris%C5%8Dma_ware

Article about soma ware
https://www.staradvertiser.com/sponsored-content/unique-somayaki-pottery-makes-comeback-hawaii/