观其形，闻其语，会其神

copy from someone's blog. for instance,in the airport,a group of ten, if one person is saying something,while the others are listening with smile and answering from time to time ,they are japanese if eight or nine in ten are speaking loudly,that's korean if five or six are talking ,the others are looking around while listening,that's chinese REASON:the Japanese emphasis on the collective priorities of the character,they would at the expense of themself to join the gourp. Koreans, even if the representatives say, they have to express their opinions No matter where ,Chinese people have the habit of looking around much on foreign soil, it's also bad habits .

Hahaha this is a funny question and I'm glade someone had the guts to ask it (I certainly didn't). Just the other day in my Physics class an American girl called a Japanese boy Korean, anyway she was pregnant I think that is the only reason why she did not get smacked, but he was completely offended. I can tell, or at least I think I can tell, the difference by mostly the attitude of the person; or at least this is how I come to a definitive answer. Overall Japanese people are reserved, Chinese people are outgoing and very nice, and Korean.... well all the Korean people I know are Americanized and they are just partier's (hahaha okay bad example). At least that is my experience. Without meeting the person I draw my conclusions from looking at their eyes. Japanese people's eyes are, for the most part, the same shape as white people's eyes. Chinese people's eyes are slanted long-wise and Korean eyes are slanted down. Also hair texture helps. Anyway, that is just a bunch of generalities that can't be used to draw definite conclusions. The best way to know for sure it to make many Japanese, Chinese, and Korean friends so that you can get to know how they are different for yourself.

Lemme tell you the easiet way to indenty a Chinese and a Japanese If you see a person meets a person, he bows (this is called お辞儀), then he must be a Japanese. If you see a person just shake his hand with the person he meets (this is called 握手する), then he must be a Chinese. About Korean people...sorry I don't know..."Anihaseyo"? hahahahaha