Interesting stuff. I know that historically Chinese civilization began in the North, and the Southerners were actually considered barbarians until about 2,500 years ago. That there can be distinctive differences in culture even now might be part of why that is.
I’ve thought it is the northerners who were the usurpers. The Manchu Qing who took over from the good Han Ming, real Chinese.
Made everyone shave their forehead and wear pigtails.