Addressing stereotyping

Last year I was assured by an Australian-Asian visiting Japan that you could easily tell which country an Asian is from. That isn't what I've heard from ethnically Asian missionaries here. I'm wondering if it is less easy to tell in Japan than in Australia? What's

Can you tell where these short-termers were from?

your experience? Can you usually tell what country an Asian-looking person is from?

It's easy to slip into stereotyping and labelling. We all like to be able to file people into boxes in our minds.

 Here's an interesting short article about a Japanese writer/artist who's husband was transferred to China. She received many "poor you, having to go to China" comments from friends. The news report is about how she set about addressing those negative stereotypes: http://ajw.asahi.com/article/behind_news/people/AJ201401200006