Who knows which countries China has relations with?

The first category, such as Japan and Singapore, consists of immigrants from China (I really don't want to admit that the Japanese are descendants of China people, which is embarrassing);

The second category, such as Mongolia or a few areas in Russia, is caused by historical reasons;

Third, China's neighboring countries, such as North Korea and North Korea, Thailand, Myanmar, Vietnam and Pakistan (excluding Pakistan), can also be regarded as a class with China, because almost all their main ethnic groups are in China.