One Marriage, Two Last Names: A Landmark Decision

One Marriage, Two Last Names: A Landmark Decision

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Japanese Marriage Last Name
Courtesy: ペイレスイメージズ1(モデル) / PIXTA(ピクスタ)
A landmark decision has ruled that a couple who married in the US can keep their different last names.


On April 21st, a landmark decision was made concerning a Japanese couple who had been married in the United States: their marriage was acknowledged as official, despite having two different last names. Though the couple has yet to be registered in a koseki, they are in line to receive “a national certificate that proves their marriage.”

The reason why this is notable is due to a controversial law in Japan. This law states that married couples must share the same last name in order to be recorded in the koseki, or the family register. The koseki system is a common point of contention when it comes to domestic affairs in Japan, as it is used to denote family trees, marriage, death and inheritance.

A Flawed System

One of the major flaws of the koseki is that it assumes that every family was born into what we would now call a “nuclear family”. Moreover, many civil rights are tied into the conditions of registration itself. For example, if one is unregistered — also known as a mukousekika — then they have no legal proof of identity or Japanese citizenship. As such, they are virtually ineligible for passports, national health insurance, enrollment in public schools, etc.

One can imagine how this rigid bureaucratic practice can be detrimental to one’s social welfare and quality of life in Japan. And in the case of a married couple with two different surnames, this division can be downright problematic.


Women are usually the ones who end up changing their names, and as such, must go through the arduous task of making all the legal updates in their daily life. They must start anew in every aspect of their lives –professionally, financially, and socially. This process causes a lot of confusion, as Julia Mio Inuma (née Onishi) writes in an opinion piece for The Washington Times:

The bureaucracy was bad enough. I had to change my surname on all official documents, including everything from bank accounts and passports to credit cards and online membership accounts. My married friends soon shared with me their how-tos for this “secretive ritual,” going through various institutions in the “correct” order, with our husbands barely aware of the whole laborious process...

After two years with my husband’s last name, Inuma, my friends still get confused when I make the reservations at restaurants. They continue to look for a table for “Onishi.” Packages sometimes don’t arrive, leaving me with messages saying “they can’t find Onishi.”

– Julia Mio Inuma, “Japan says married couples must have the same name, so I changed mine. Now the rule is up for debate.“, The Washington Post, March 12, 2021.


Members of the LDP will often cite that every family must have the same last name for the sake of family unity. However, it’s the author’s opinion that there is an imbalance in this unity, where the woman is sacrificing her identity and personal history for the sake of superficial sameness.

A family sharing the same last name doesn’t ensure domestic bliss, nor does it stave off the probability of family dysfunction. Rather, a unity that is based on all members having full, legal agency over their individual identities, gives the family a fighting chance of thriving together.


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Thalia Harris

Thalia-Marie Harris is a North Jersey/New York native, currently residing in Tokyo, where she works as an ESL teacher and freelance writer. Her previous pieces have appeared in Metropolis Tokyo and pacificREVIEW.

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