Shuimo

I'm such a bad manga fan. And a bad fan of other cultures' clothing?!? But I mean I'm not just drawing a thing, I'm needing to write a description of a thing! OH I'M SO AWKWARD. DX *sob* So I'm hoping someone here will be able to help me. I'm googling, but am failing to come up with the correct keywords and kind of need to solve the mystery sooner rather than later. SO I know that layers are typical, though not so much now with centralized heat and air. I'm looking at these photos and wondering what these three robes are, what are their various functions are, if they're worn beneath other type of robe?? This specific query deals with Japan