Is it normal to date your cousin in Japan?
Depends.It depends
Dating a cousin in Japan is legal, but it isn’t especially common today, and people’s family or social reactions can vary. If you mean a first cousin, marriage is also legally allowed in Japan.
It can happen, but it’s not something most people would consider an everyday relationship. In Japan, first cousins are legally allowed to marry; whether relatives feel comfortable with a particular relationship depends on the family and the people involved.
So it’s less a clear-cut “normal or not” and more a matter of personal and family attitudes. If you’re both consenting adults, the main things to consider are your own boundaries and how the relationship could affect family dynamics.