posting here for visibility since this has happened more than once on MU and im assuming it's a few people doing this.
i have seen manga/manhwa mistagged as ancient japan or ancient korea. if you're not familiar with other cultures (obviously i dont claim to be an expert on every culture) it's easy to mistake some styles of hanfu for kimono, or even think that a story that is set in vietnam is set in thailand (yes, i've seen these happen).
im aware of korea and china's recent disputes over claims on some aspects of their culture, however (im not well-versed myself so correct me if im wrong), it looks she is wearing Qixiong Ruqun and the emperor mian liu.