Chihiro's work clothes - imaginary or real? (Spirited Away, directed by Hayao Miyazaki)?

It's bugged me for a long time, not knowing what kind of clothing it is! With split shoulders, a front holding pouch (incidentally, I think), a high and round collar, it looks nothing like a kimono or a happi so I suspect that this is another creation of Hayao Miyazaki and his staffs, may be. If you know any better, please tell me. Thank you.