①A child conceived by a wife during the marriage is presumed to be the child of the husband in that marriage. The same applies to a child conceived by a woman before the marriage and born after the marriage is formed.

②In the case referred to in the preceding paragraph, a child born within 200 days of the formation of a marriage is presumed to have been conceived before the marriage, and a child born more than 200 days after the formation of a marriage or within 300 days of the dissolution or cancellation of a marriage is presumed to have been conceived during the marriage.

③In the case referred to in paragraph (1), if a woman has entered into two or more marriages between the time she conceived the child and the time of the child's birth, the child is presumed to be the child of the husband in the most recent marriage as of the child's birth.

④In the application of the preceding paragraph to a child for whom a father has been determined under the preceding three paragraphs in a case where it has been rebutted under Article 774 that the child is the child in wedlock of that father, the phrase "the most recent marriage" in that paragraph is deemed to be replaced with "the most recent marriage (excluding the marriage with the husband as to whom the presumption that the child is his child in wedlock has been rebutted under Article 774)".

If a woman marrying in violation of the provisions of Article 732 gives birth and the paternity of the child cannot be determined pursuant to the provisions of the preceding Article, the court determines the paternity of the child.

①In a case where the father of a child is determined pursuant to the provisions of Article 772, the father or the child may rebut the presumption of the child in wedlock.

②The child's right to rebut the presumption under the preceding paragraph may be exercised on behalf of the child by the mother exercising parental authority, the adoptive parent exercising parental authority, or the guardian of a minor.

③In the case prescribed in paragraph (1), the mother may rebut the presumption of the child in wedlock; provided, however, that this does not apply if it is clear that the exercise of the right to rebut the presumption would harm the interests of the child.

④In a case where the father of a child is determined pursuant to the provisions of Article 772, paragraph (3), a person other than the father of the child who was married to the mother between the time of the child's conception and the time of the child's birth (hereinafter referred to as the "former husband") may rebut the presumption of the child in wedlock; provided, however, that this does not apply if it is clear that the exercise of the right to rebut the presumption would harm the interests of the child.

⑤A person who has exercised the right to rebut the presumption under the preceding paragraph and has newly been determined to be the father of the child pursuant to the provisions of Article 772, paragraph (3) as replaced pursuant to the provisions of paragraph (4) of that Article may not, notwithstanding the provisions of paragraph (1), rebut the presumption that the child is his child in wedlock.

①The rights to rebut the presumption set forth in the following items are exercised through an action to rebut the presumption of the child in wedlock against the person specified respectively in those items.

②If a right to rebut the presumption set forth in item (i) or (iv) of the preceding paragraph is to be exercised against the mother exercising parental authority and there is no mother exercising parental authority, the family court must appoint a special agent.

If a father or mother acknowledges, after the child is born, that the child is his or her child in wedlock, the father or mother, respectively, loses his or her right to rebut the presumption.

An action to rebut the presumption of the child in wedlock pertaining to the exercise of a right to rebut the presumption set forth in each of the following items must be filed within three years from the time specified respectively in those items.

If, with respect to a child whose father was determined pursuant to the provisions of Article 772, paragraph (3), the presumption that the child is the father's child in wedlock has been rebutted pursuant to the provisions of Article 774, an action to rebut the presumption of the child in wedlock pertaining to the exercise of a right to rebut the presumption set forth in each of the following items must, notwithstanding the provisions of the preceding Article, be filed within one year from the time specified respectively in those items.

①If, during the six months before the expiration of the period under Article 777 (limited to the part pertaining to item (ii)) or the preceding Article (limited to the part pertaining to item (ii)), there is no mother exercising parental authority, adoptive parent exercising parental authority, or guardian of a minor, the child may file an action to rebut the presumption of the child in wedlock until six months have passed from the time when the period of suspension of parental authority of the mother or adoptive parent expires, a ruling rescinding a ruling affirming the loss of parental authority or a ruling to suspend parental authority becomes final and binding, or parental authority is restored, the time when a new adoption is formed, or the time when a guardian of a minor takes office.

②If the period during which the child has continuously lived with the father (or, if there are two or more such periods, the longest of them) is less than three years, the child may, notwithstanding the provisions of Article 777 (limited to the part pertaining to item (ii)) and the preceding Article (limited to the part pertaining to item (ii)), file an action to rebut the presumption of the child in wedlock until the child reaches the age of 21; provided, however, that this does not apply if the exercise of the child's right to rebut the presumption would significantly harm the interests of the father in light of the circumstances of upbringing by the father.

③The provisions of Article 774, paragraph (2) do not apply in the case referred to in the preceding paragraph.

④An action to rebut the presumption of the child in wedlock pertaining to the exercise of the right to rebut the presumption set forth in Article 777 (limited to the part pertaining to item (iv)) and the preceding Article (limited to the part pertaining to item (iv)) may not be filed after the child has attained the age of majority.

Even if the presumption of the child in wedlock is rebutted pursuant to the provisions of Article 774, the child is not obligated to reimburse the costs required for the custody of the child that were expended by the person who was the father.

In a case where, after the opening of the succession, a right to rebut the presumption has been exercised pursuant to the provisions of Article 774, and a person for whom the decedent has been newly determined to be the father pursuant to the provisions of Article 772, paragraph (3) as replaced pursuant to the provisions of paragraph (4) of that Article seeks, as an heir, to request division of the estate, if the other coheirs have already divided or otherwise disposed of the estate, the request of that heir for division of the estate is to be made only by a request for payment of the value.

A father or a mother may acknowledge a child born out of wedlock to be his or her child.

A father or a mother does not need the consent of a legal representative in order to acknowledge parentage, even if that father or mother is a minor or an adult ward.

①Parentage is acknowledged through the filing of a registration pursuant to the provisions of the Family Register Act.

②Parentage may also be acknowledged in a will.

A father or mother may not acknowledge parentage of an adult child without that adult child's consent.

①A father may acknowledge paternity even if the child is still in utero. The mother's consent must be obtained in such a case.

②If the child referred to in the preceding paragraph is born and the father of the child is determined pursuant to the provisions of Article 772, the acknowledgment under that paragraph does not take effect.

③A father or mother may acknowledge parentage even if the child has died, but only if that child had a lineal descendant. In such a case, the consent of the lineal descendant must be obtained if that lineal descendant is an adult.

An acknowledgement of parentage is effective retroactive to the time of birth; provided, however, that this may not prejudice a right already acquired by a third party.

A father or a mother who has acknowledged parentage may not rescind that acknowledgment.

①The persons set forth in the following items may file an action to invalidate an acknowledgment of parentage, on the grounds that there are facts contrary to the acknowledgment, only within seven years from the time specified respectively in those items (or, in the case where the acknowledgment was made pursuant to the provisions of Article 783, paragraph (1), the time of the child's birth); provided, however, that this does not apply to the person set forth in item (iii) if it is clear that the assertion of invalidity of the acknowledgment would harm the interests of the child.

②If the period during which the child has continuously lived with the person who acknowledged the child after the acknowledgment (or, if there are two or more such periods, the longest of them) is less than three years, the child may, notwithstanding the provisions of the preceding paragraph (limited to the part pertaining to item (i)), file an action to invalidate the acknowledgment of parentage until the child reaches the age of 21; provided, however, that this does not apply if the child's assertion of invalidity of the acknowledgment would significantly harm the interests of the person who made the acknowledgment in light of the circumstances of upbringing by that person.

③The provisions of the preceding paragraph do not apply where the legal representative of the child prescribed in that paragraph files the action to invalidate an acknowledgment of parentage under paragraph (1).

④Even if an acknowledgment is invalidated pursuant to the provisions of paragraphs (1) and (2), the child is not obligated to reimburse the costs required for the custody of the child that were expended by the person who made the acknowledgment.