One of the purposes of Japan’s koseki (family register) system, if not the main purpose, is to provide the authorities with some control over what constitutes a family, which naturally leads to grey areas and points of contention, since it’s usually families themselves who define what they are, and they can differ significantly from one to another in terms of structure and makeup. One of the central means of exerting this control is for the government to insist on having the last say on who is the father of a child. Determining the mother is easy and incontrovertible: it’s the person who gives birth. Paternity, however, is more or less a matter of taking somebody’s word for it, usually the mother but sometimes the nominal father, and until DNA tests became practical there was no empirically effective way to determine paternity of a child, so the government made rules that would essentially give it the right to approve who the father is.

Under the circumstances that are considered “normal” by the authorities, meaning a married heterosexual couple who produce a baby through sexual intercourse, the process of determining paternity is straightforward and glitch free. But anything that veers away from this scenario invariably causes problems for the bureaucrats whose job it is to implement the government’s acknowledgement of paternity, and one of the most contentious situations in this regard is when a woman has divorced and then remarried within 300 days of the divorce’s finalization and, during this period, given birth. Under present law, the paternity of the child is acknowledged to be the previous husband, since the government has determined that the gestation period of a human baby is 300 days and thus there is the possibility that the baby could have been conceived on the eve of the finalization of the divorce. It doesn’t matter how long the couple in question had been separated prior to the finalization, nor how long the woman and her subsequent husband had been in a relationship before the baby’s birth. The government doesn’t want to bother with such uncertainties, and so formulated an arbitrary cut-off point that makes it easier for them to register the child’s father in the koseki. 

For years, this 300-day rule has been the subject of lawsuits and editorial criticism, and apparently the justice ministry is finally getting around to amending it so that the law makes more sense. An article in the Feb. 2 Asahi Shimbun described a legislative sub-committee in the ministry that has been reviewing the government’s “assumption of paternity” privilege and plans to submit a proposal for revising it. They will do this by adding an “exception” to the present law that says if the mother of the child has remarried “in the meantime,” then the father of the child is her new husband. Consequently, the married couple is considered to be the parents of the child. This sounds straightforward, but in order to make the exception bureaucratically acceptable, the law also has to remove another part of the Civil Code associated with the 300-day grey area, which is that a woman is forbidden from marrying for 100 days following the finalization of her divorce. The justice ministry, according to Asahi, says it plans to revise the law as soon as possible through Diet legislation. 

This system for determining legitimacy was first stipulated in the Civil Code in 1898 for the purpose of “stabilizing the legal status of a child by confirming the child’s father at an early stage,” regardless of any genetic relationship, which was impossible to determine scientifically at that point. Basically, it means that a child is the natural issue of the husband of the mother. The 300-day corollary was added to address situations that didn’t fall into this neat box. However, in more recent years there have been women who have left their husbands due to domestic violence or other reasons and subsequently borne children by other men. And due to the fact that they don’t want their former mates, whether they remain married or not, to be acknowledged as the fathers of the resulting children, these women do not report the births to the authorities and thus the children do not have family registers. That is a problem for the government, since it undermines their authority in determining what a family is. According to Asahi, as of January, the justice ministry says there are 825 nominally Japanese people with no koseki, which means those people do not technically have any nationality, and of these 591, or about 70 percent, have no koseki due to legitimacy concerns on the part of the mother. 

The thinking is that by revising the law to make it possible for these women to claim their new partners as the fathers of their children even within the 300-day period, more will avail themselves of family registers. As mentioned above, the law prohibits a woman from marrying for 100 days following her divorce, based on the somewhat unrealistic idea that a woman will not have sexual intercourse until she is formally married. If she remarried on the day after her divorce but was somehow pregnant with a child by her previous husband, there would be all sorts of bureaucratic headaches. So in order to finalize the exception of accepting the new husband as the father of any child born to the woman while they are married, the ministry has to eliminate this 100-day prohibition (which implies that the grey area of paternity, by the authorities’ logic, only applies from the 101st day after the divorce to the 300th day) and allow a woman to marry as soon as possible after her divorce. 

Another change that will be incorporated into the revision involves the right of a father to claim or deny paternity. At present, only the male interested party can deny his paternity of a child, but after the revision, the female party, meaning the actual mother, can refute a man’s claim to paternity. The mother’s say in the matter will now be the privileged opinion, whereas presently it is the nominal father’s say. Presently, if the man who is considered the father denies paternity or does not actively become involved in registering the birth of the child, the child will automatically be deemed illegitimate, regardless of what the mother says. This is usually done through nomenclature: a legitimate child in the koseki is listed as “first son/daughter,” “second son/daughter,” etc., while an illegitimate child is simply listed as “boy” or “girl.” Under the revision, any man who claims paternity of the child will be deemed the father and the child is considered legitimate, but only if that man is married to the mother. This obviates the need for a man who is not the biological father of the child to adopt the child as his own. If he is married to the mother, then he is considered the child’s father. 

Again, this all sounds like common sense, but one has to take into consideration the purpose, which is to maintain the koseki system, without which all these bureaucratic gymnastics would be unnecessary. Terms such as “legitimacy” and “paternity” only apply to married couples and their offspring. (The treatment of common law arrangements seems to depend on the bureaucrat.) If a couple who is not married has a child, none of these things apply, which is why Japanese people feel they have to get married. Otherwise, their children will face lives of officially sanctioned discrimination for being “illegitimate.” The family register system is more important than the existence of groups who think of themselves as families but which the government doesn’t recognize as such.