According to the Japanese Civil Code, direct blood relatives or collateral blood relatives within the third degree of kinship are not allowed to get married, while other relatives can apply for marriage registration. The relationship between cousins is classified as a fourth degree relationship in Japanese law and is not within the scope of legal constraints. Therefore, in Japan, cousins can get married.
Attitudes of various countries towards' consanguineous marriage '
Deep blue represents that consanguineous marriage is legal, red represents that laws prohibit consanguineous marriage, light blue represents that consanguineous marriage is allowed to be legal with restrictions, orange represents that legality depends on religious doctrines, pink represents strict prohibition but exceptions, brown represents that consanguineous marriage is a criminal offense, and gray represents that there is currently no data available.
Most countries in Europe, Australia, and the Americas allow consanguineous marriage.