Marriage

The male partner must be 18 years ofage or older and the female partner must be 16 years of age or older.
In addition, for Americans, you must be able to legally marry in your home state; if the legal age of marriage at home is 18, you cannot marry earlier than that in Japan.
A woman cannot get married within six months of the dissolution of her previous marriage. According to Japanese law, this is to avoid confusion as to the identification of a child's father if a birth occurs close in time to the end of the marriage.
Most people related by blood, by adoption or through other marriages cannot get married in Japan.
A person who is under 20 years of age cannot get married in Japan without a parent's approval.