How many children can Japanese people have?

I have heard that people in Japan can only have a set amount of children and if they go over that amount they have to get permission. Is this true or did it ever used to be true? And if it is, or was, how do, or did, they regulate it? Any information would be helpful. Thank you.
Update: So maybe I was confusing Japan with China. Thank you for correcting me. Any information reguarding CHINA would help. Sorry guys.
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