Also, ignorant question here. Please clarify for me. Is there a physical difference between people of different Oriental groups, such as Japanese, Chinese, Korean. In other words, without knowing one's cultural background, could someone physically see the difference between a Japanese person and a Chinese person?
Oh, definitely. In fact, there are multiple different ethnic groups within both Japan and China. The dominant ethnic group in Japan is called the Yamato people, while the dominant Chinese ethnic group is the Han, but there are minority ethnic groups in both countries -- especially in China, which has dozens of ethnic minorities, since it's so huge.
There's a theory that the Japanese and Koreans have a common origin, but it's hotly disputed because ethnic and political tensions get in the way of the science.