People of Japan: Not Japanese

I finally realized that "Japanese" and "people of Japan" may have different meanings for younger kids--younger than 7 years old. When I ask 5- and 6-year-olds "Have you seen a Japanese?" most of them say "no." But those kids understand "Japan" and recognize a Japanese national flag. So, maybe they could understand a "person of Japan" if not a "Japanese." I should have realized this earlier because I knew that 2nd graders often use the expression a "person of Japan" to refer to a Japanese. Perhaps, kids develop a concept of the place called "Japan" first. Then, they associate the place with certain people, essentializing their relationship. Eveventually, the concept of a "person of Japan" develops into that of a "Japanese"...?