China Or Porcelain? Demitasse set

I just bought this set from an antique store but they did not know anything about it. I don't know if it is china, porcelain or...... I have no idea if it is antique or vintage. I don't know who made it because there are no markings.

The set contains 6 cups that hold 4 oz ea, 5 saucers and 2 larger plates.

Pic 1 is obviously the cup and saucer
Pic 2 is just the saucer
Pic 3 is the cup and saucer looking down on it
Pic 4 is the plate

The bottom of the cup is square
The saucer has a square center which holds the cup
The plate does not have any indentation in the center

If anyone can help identify this set, I sure would appreciate it.

Thank you so much