China/Porcelain tea set - Made In Japan

Hi

I wonder if anyone is able to throw any light on a tea set that I have. I don't know if it's china or porcelain. It's some years old (at least 65-70 years), stamped Made In Japan, with a Japanese design, quite thin and light, but I cannot decipher what the marks mean on the base of the pieces. I haven't yet been able to identify anything similar to the markings. Has anyone come across anything similar?

Thanks