@evergreen5 Decades ago, it was very difficult for Chinese citizens to be allowed to leave the country. That only started to change about 25 years ago. They still have to apply to leave the country. The law says “Approval to exit from the country shall not be granted to persons…persons whose exit from the country will, in the opinion of the competent department of the State Council, be harmful to state security or cause a major loss to national interests.” https://www.fmprc.gov.cn/ce/cgny/eng/lsqz/laws/t42218.htm