China is simply too big,there isn't just one type of looks,there are prolly over 100 types of look.
The origin og chinese was from norther west china,ofcause they shows northern look.
A lot of korean women nowdays get surgerys just ot have that type of look.
Ofcause the chinese were mixed. No country in this world is pure,everybodys mixed.
Thats very ood,consider that the cradle of chinese civilization was from northern china,far from se asia. Not to mention Chinese are grouped with east asians in every academic paper or books.
I would like to know how did those korean scholars derived this from? 
Yes, China is very big; so you will have much more varieties of people, most Southern looks in Korean peninsula are result of migration from east coaster regions of China, not from Vietnam/Thailand regions. If you look at the map of Korean peninsula, center of China is located more South than Korean peninsula, so Southern look in Korean peninsula doesn't mean they were originated from SE Asian region.
These women on the exhibit photo are not result of surgery, they just simply picked more attractive women.
Mind you even with high demand of cosmetic surgery in South Korea (not North), basic facial structure remains unless you are taking extreme plastic surgery.
Japanese and Taiwanese spent more than double of South Koreans on plastic surgery in terms of per capita. Since you did bring this up.
http://www.nationmas...gery-proceduresAs I wrote before, these came out of China to Korea aren't just Northern race, many were also originated from SE China.
Even with cradle of civilization originated from the Northern China, due to agricultural boom & warmer climate in the southern regions, there are more Southerners in terms of population in China.
As I mentioned before, to Korean geneticists and scientists, they usually regard Chinese people as SE Asian group that doesn't mean all Chinese are SE Asian origins and don't ask me why? because I don't know the answer to that. This Korean book also suggested Japanese are also show more Southern looks than Northern looks. So, I'm thinking Southern looks doesn't mean SE Asian look.
Please stay on the topic, we discussing about Southern/Northern looks of Korean not Chinese or other people.
If you got question about why Koreans scholars group Chinese as SE Asian group then ask them the question, not me.
Edited by SNK_1408, 03 December 2008 - 11:01 PM.