Japanese mothers seem to control their kids with an absolutely expert use of the kind of emotional blackmail that a Western parent might feel embarrassed about, plus a good dollop of indulgence and other manipulations. The net total result is a kid who will feel so upset themselves at displeasing their parents (mainly the mother), that no other punishment is needed- a child that will often grow up into an adult with much the same mentality. Another reason you would rarely see temper tantrums etc. if you are not part of the family is that a Japanese child quickly learns that different behaviour is suitable for different circumstances, and there is no such thing as “acting naturally” or “being true to yourself”.
More on this question in this New York Times article