This is a 39Arita Double Wall Cup (two-layer structure) that uses the 400-year-old traditional technique of Arita porcelain.
The double wall cup is easy to use and has excellent heat and cold insulation, so you can hold hot drinks with your bare hands and keep cold drinks from condensation.
It does not have a handle like a regular mug, so it can be stacked and takes up less storage space, making it perfect for use at home or as a commercial cup.