Thank you for the information.
About the name "Kinh" to describe yourself as of Vietnamese ethnicity, I heard of a story of the origin of the first use of this word to refer to northern Vietnamese in China but do not know how true it is since the use of the word "Kinh" (Gin/Jing;京) when referring to Vietnamese people in China dated back to the 1600s. Maybe someone here can confirm?
The story goes that during the 17th-19th century, in China, if you were to ask a non-Manchus where the king reside, they would say to the South, where the capital is at (perhaps as an act of defiance against the Qing monarchy or perhaps they felt that Viet monarchy was a much closer kin to their former Ming than the ruling Qing). Therefore, the name Kinh is still used to this day to refer to Vietnamese living in China. Nevertheless, this views may have changed as the influences of the Qing monarchy and power spread throughout China.
As I know today, traveling through Vietnam, southern Vietnamese refer to northern Vietnamese as "Bắc Kỳ" (Northern Flag) and Vietnamese people refer to themselves as "người Việt" to foreigners and use "người Kinh" to differ themselves from the ethnic minorities in Vietnam.
I don´t have the info when the term "kinh" came into existence, and still have to search a bit more to find out. kinh is most likely derived by jing in chinese: Beijing (northern capigtal), Nanjing (southern capital).
basically the vietnamese people consist of 86% of ethnic kinh as majority and 14% of the ethnics as minority (54 groups such as Tay, Tai, Hmong, Hoa, Khmer, Nung, and many others).
who are the kinh people?
yes, Kinh means capital, here Hanoi city or more precise the Red river delta. the region is the place when the first Vietnamese settled down and cultivated the land. Unlike the Kinh, many other ethnics live in mountainous regions. So the kinh distinguish themselves from others by geographic locations. the Kinh live mainly in cities and coastal regions.
apart from that, the Kinh have different cultures and custom than other ethnics. so basically Kinh are sinized people. I understand, the recent genetic study of Harvard medical school shows the Kinh´s ancestors originated from Taiwan. our forefathers came to the present day Vietnam before 5,000 years ago. according to this study, the likelyhood is extremely high, the Taiwanese came as seafather and settled down in the red river delta. so Kinh people have chinese roots.
Austronesien: Südseebewohner: Aus Taiwan über Vietnam nach Polynesien? - Spektrum der Wissenschaft
Also, the DNA study of the hospital Saint-Louis in Paris confirmed the assumption that the Vietnamese population has evolved from the tai/Indonesian and the southern Chinese population.
Vietnamesen – Wikipedia
some studies show a different picture. the first Vietnamese originated from austronesians. they came from the western pacific. some genetic research show the Viet people have mixed with the mongolians, who came as settlers to Vietnam.
so, we don´t know for 100 per cent. Perhaps more future researches can bring more light into this.
Yes, the people of Gin/Jing;京 is Vietnamese migrants, who came to China hundreds of year ago. they belong to one of the recognised minorities in China.
China Wiki – The free encyclopedia on China, china.org.cn
yes, you are right at the last part. "Bắc Kỳ" is northerner.