While Chinese and Japanese people are both from the Asian continent, they are from two different countries: China and Japan. Much like many European countries, the people from the continent share many physical similarities, but also distinct differences.
China is a much larger country than Japan, both in size and population. China has a population of 1.2 billion compared to about 127 million Japanese residents. Japan is unique in that it is almost completely surrounded by the Pacific Ocean, which explains the substantial fish component of a typical Japanese diet. Japan has one of the most homogeneous populations in the world.