When I lived in Korea it was explained to me that farmers and peasants had darker complexions because they were out in the sun all day. Having lighter skin was a matter of class distinction, and it had nothing to do with Western influence.
That argument strikes me as disingenuous. Being fat used to be a class distinction (poor people couldn't afford to be fat) but it's not popular today. I suspect preference for lighter skin color is more self-racist than people like to portray (even to themselves).
Actually, lighter skin used to be an issue for westerners too. Lighter skin suggested the same thing as it did in Asia and tanned skin was looked down upon. Recently, with the massive changes in the economy over the past hundred or so years, tanned skin has begun to demonstrate leisure and wealth more than paleness, so the situation has reversed. Korea and Japan have modernized much recently than America and the West so that could be the reason.
I think the preference for lighter-colored skin in China dates back to when they thought westerners were ugly, smelly barbarians. That isn't to say that modern perceptions of whites as modern and superior isn't a factor now, but it is a relatively late influence on the phenomenon.
