My first thought is 'The Eyes' NOT a particular country.
I am sure it depends on your personal experience with Asians. I tend not to use the term Asians very much because it is too broad a term. But having been in China, Japan, Malaysia, Indonesia, Thailand and several other countries in East Asia, South Asia and Southeast Asia, the differences between the nationalities are quite apparent. I think this is the same as talking about Latinos or Hispanics. People from Mexico are different from people from Puerto Rico or the Dominican Republic or one of many other South American or Spanish-speaking countries.
I myself is an Asian but the first thing I really think of is Chinese. Maybe its because they have a big population and every country seems to have a Chinese citizen.
I don't think any specific country, although China would be a good guess considering it is absolutely gigantic. If I can see the person, I might think a country ba<x>sed on the way they look though.
Well can't compete with highest population!!!
There are over two billion people in the world who could be called Asian. I don't think of any one type when I hear the term.