Starting in the fifteenth century, leaders in China and Japan decided to cut off contact with other countries.
What was not a reason for doing this?
They feared European nations might some day threaten their rule.
They feared European nations would see how poor and underdeveloped the Chinese and Japanese civilizations were.
They feared their people would no longer be self-sufficient and would rely on trade with foreigners.
They feared outsiders wanted to change their traditional practices and beliefs.