SHIHA TEAPOT SHOP Online Store: https://shihateapot.com
Reiko Red Clay Smoked Black (Red Rim) Cup Set 6 pcs.
This item matches to the teapot of Reiko.
Inside of the cup will have white brushing paint.
This is to help to look color of tea liquid well.
Reiko Teapot Page
Shape is elegant and proper for Japanese senchado, too.
Regarding quality of the clay, please read a page below (Black teapot page)