Summary of Procedures: Separate Surnames for Married Couples - When a Child is Born to a Common-Law Couple
We have been living as a common-law couple with separate surnames since June 2021...
Thanks to everyone's support, we were blessed with our first child, who was born in June 2022.
Even after the birth of our child, we have continued to maintain separate surnames!!!
In this note, I would like to write about the topic of "When a child is born to a common-law couple with separate surnames," as well as the specific procedures involved.
If you are wondering:
・What happens when a child is born?
・I have information about couples, but there is no information about children at all...
・I want to know about "separate surnames for married couples," which is a hot topic in society.
Then I think this note will be useful for you.
Before the child...
・What is a common-law marriage in the first place? Pros and cons
・How can we become a couple with separate surnames/common-law marriage?
・What is a common-law marriage contract? What is its purpose and how do you create one?
If you want to know about these, please take a look at this note first ↓
Now, let's get started!
What happens if you do nothing
If you do not perform any procedures, the father will be unknown (!)
The child will be entered into the mother's family register, with the mother's surname and the mother as the person with parental authority, resulting in a situation similar to that of a single mother.
Mother: Marie Omutake
Child: Torakichi Omutake (pseudonym)
Hideyuki Kusaka, the father, remains a stranger.
If nothing is done, no legal father-child relationship will be established between the father and the child.
What procedures are necessary? Three perspectives
The necessary procedures change based on the following three perspectives:
1. Whether to establish a legal father-child relationship between the father and child
2. What to do about the child's family register (≒ surname)
3. Who will have parental authority over the child
1. [Acknowledgment] Whether to establish a legal father-child relationship
"Acknowledgment" means admitting that "I am the parent of this child." Since the mother gives birth, she is automatically recognized as a legal parent, but in the case of an unmarried couple, it is unknown who the father is. If nothing is done, the child's family register will remain "father unknown," and rights of inheritance, as well as duties of support and upbringing, will not be established.
Therefore, I recommend that you proceed with the "acknowledgment" procedure without hesitation.
Specifically, the father should submit an "Acknowledgment of Paternity" to the municipal office during pregnancy or after the birth.
The timing does not matter, but personally, I recommend doing it "during pregnancy" (i.e., acknowledgment of a fetus)! The reason will be explained later.
Once accepted, a legal father-child relationship is established between the father and the child.
(By the way, this acknowledgment cannot be revoked unless it is proven through DNA testing that the child is not his.)
2. [Family Register and Surname] The Unavoidable Reality of Different Surnames for Parent and Child
In short, the issue of what to do about the surname. When a child is born, you must decide whether the child will take the father's or the mother's surname.
This means that "the child will inevitably have a different surname from one of the parents."
This is an unavoidable fact, and it is also a point often raised by those who oppose separate surnames for married couples. (e.g., "What about family bonds?" or "Won't they be bullied?", etc.)
In fact, I myself grew up as the only one in my family (mother & older sister) with a different surname.
However, I have never felt that family bonds were damaged, and I have never experienced being "bullied" because my surname was different from my mother's.
Personally, I think that such a way of thinking is actually a manifestation of discriminatory consciousness...
In the first place, everyone definitely has a different surname from one of their grandparents, so I think it's nothing to worry about. That is just my opinion, though.
3. [Parental Authority] You Cannot Have Joint Parental Authority in a Common-Law Marriage
In a common-law marriage, you cannot have joint parental authority.
To begin with, what is "parental authority"...
To put it simply, it is the right to manage the child's bankbook, sign up for a smartphone, or consent to surgery until the child reaches adulthood.
In the case of a child born to a legally married couple, both parents hold parental authority over the child. (= Joint Parental Authority) However, in the case of a common-law marriage, only one parent can hold parental authority. (= Sole Parental Authority)
We often hear about "custody battles" during divorce, but as long as a couple with separate surnames trusts each other, I personally think there is no need to be too concerned about parental authority.
This is because even if you do not have parental authority, a parent and child are still a parent and child.
As long as you acknowledge the child, you both have the obligation to support and raise them, and they become your heirs. Not having parental authority does not sever the parent-child bond.
The only time sole parental authority might be inconvenient is when you can only write one parent's name in the "Parental Consent Form" section, or when only one parent can handle things when "accompanied by a parent/guardian" is required.
That said, my child will be one year old soon, but such strictness has not been required at daycare or the hospital, and since they are usually just called "[Child's Name]'s mother," there is no occasion to mention my surname.
So, when is strictness required? Well...
- When applying for something at the court
- When issuing a passport
- When opening a bank account
and so on. It is not something that happens frequently in daily life.
In other words, I think it can be managed if the parent with authority handles it only at those times.
There are the following 6 patterns for the child born
When thinking from the above three perspectives, the possible options are the following 6 patterns.
I have the impression that many people choose 2 and 5.

To explain briefly...
① is the "do nothing" pattern mentioned earlier.
Father: Unknown
Mother: Marie Omutake
Child: Torakichi Omutake (pseudonym) Custodian: Mother
The family register will continue to show "Father Unknown," and considering subsequent procedures and child-rearing, I do not recommend leaving it as ①...
② is the pattern where both the child's surname and custody are with the mother.
Father: Hideyuki Kusaka
Mother: Marie Omutake
Child: Torakichi Omutake (pseudonym) Custodian: Mother
It is completed simply by submitting a "Notification of Acknowledgment" during pregnancy or after birth.
If you are okay with the husband and child having different surnames, I think this pattern is the best. After all, the procedures are easy.
(Also, even if the husband is fine with it, what the in-laws think is another matter. It might take some courage to tell the in-laws.)
③ is the pattern where the child's surname is with the mother and custody is with the father.
Father: Hideyuki Kusaka
Mother: Marie Omutake
Child: Torakichi Omutake (pseudonym) Custodian: Father
The procedure is simple as you only need to submit a notification of custody to the municipal office.
However, as I will explain later, I personally think it is better for the "surname" and "custody" to be with the same person...
④ is the pattern where the child's surname is with the father and custody is with the mother.
Father: Hideyuki Kusaka
Mother: Marie Omutake
Child: Torakichi Kusaka (pseudonym) Custodian: Mother
I grew up in this pattern. However, as with ③, I will explain later, but I personally think it is better for the "surname" and "custody" to be with the same person...
Also, an application to "keep custody with the mother while changing the child's surname to the father's" may not be approved by the Family Court.
⑤ is the pattern where both the child's surname and custody are transferred to the father.
Father: Hideyuki Kusaka
Mother: Marie Omutake
Child: Torakichi Kusaka (pseudonym) Custodian: Father
If you want the child's surname to be the father's, this is recommended. First, transfer custody to the father via a notification of custody. By doing so, the application for "permission to change the child's surname" at the Family Court is more likely to be approved. When a mother who does not have custody performs any procedures, a power of attorney is essential. If an agent is not allowed, the mother cannot do anything. Father, do your best.
⑥ is a pattern that results in the same outcome as ⑤, but the procedure method is different.
Father: Hideyuki Kusaka
Mother: Marie Omutake
Child: Torakichi Kusaka (pseudonym) Custodian: Father
This is a pattern where the child is considered the father's child in the form of an "adopted child." When adopted, the child's surname and custody are automatically transferred to the father. Although they are the biological parents, it is unavoidable that the word "adopted child" will appear in the family register.
In the end, which one did we choose? In the case of the Kusaka & Omutake family
We decided to go with this pattern for our family.

The reasons are mainly the following five.
1. As long as I am an "Otake"
The first thing I thought was that as long as I am an "Otake," it doesn't matter which surname the child has. Having lived as "Marie Otake" for 26 years, my name has become part of my identity, and I have a strong desire to cherish it in the future as well.
On the other hand, regarding the child, I felt that whether they are an "Otake" or a "Kusaka," they are still my precious child regardless.
2. "Otake" is a bit of a hassle (lol)
The surname "Otake" comes from descendants of samurai in Okayama, and it's a rare surname with only about 30 people in the whole country, but well, people just can't read it. Lol
It's never taught in elementary school, no matter how long you wait, and it has an excessive number of strokes. No matter how hard I try to explain it on the phone as "Outake," it becomes "Ootake"... And when I forget my personal seal, I can't just solve it instantly at a 100-yen shop. It's quite a troublesome surname.
On the other hand, it has an impact, so I recommend it to people like me who value uniqueness. Lol. However, since it stands out, I sometimes wonder if it might be too intense depending on my child's personality? Lol
I thought that "Kusaka" is a kanji learned in elementary school, has fewer strokes, isn't as intense, and probably won't be misheard as often.
3. To be a grandchild of the "Kusaka family"
When I first talked about wanting to have separate surnames, my father-in-law said this:
"I want my son, a Kusaka, to live his life bearing the name Kusaka. So, I have resistance to my son bearing a different surname. However, regarding a common-law marriage where you maintain each other's surnames, if that is what you both wish..."
A year has passed since then. I didn't bring it up again, but I started thinking on my own, "Wouldn't it make them happier if not just their son, but also their grandchild bore the name Kusaka...?"
Since I don't have a strong preference, I think it's better if more people are happy, and honestly, I feel that my parents-in-law have accepted my selfish desire to "want to have separate surnames." So, there was also an ulterior motive that if giving the child the husband's "Kusaka" surname makes future relationships smoother, then...
4. Because I love my "husband" and my "husband's family"
The family I have met so far that I think is the most wonderful is the Kusaka family. (For details, see my note The 'family' I wanted when I was a child)
I also have a feeling that it would be nice if my child could also become like that by living as a "Kusaka." (Well, family bonds aren't built by surnames, though.)
I want to remain an "Otake" myself, but I thought it would be somehow better for my child to bear the surname of my beloved husband and the family I admire.
I'm sure you don't know what I'm talking about. I got lost while writing it too. Lol. I will add more if I come up with a better way to express it.
5. From experience, it is better for the 'Family Register' and 'Parental Authority' to be with the same person
For the four reasons above, we decided to keep the 'Family Register' with Kusaka, but then the issue of what to do about 'Parental Authority' emerged.
When I was 15, my parents divorced, and I grew up in an environment where
Family Register: Father
Parental Authority: Mother
.
I wrote about this in detail in this note I have lived with a different surname from my parent for 10 years, but when the 'Family Register' and 'Parental Authority' are separate, there were minor obstacles like the following.
The stress of being asked, 'What is your relationship to this person?'
When I had to submit a parental consent form to school, if my surname was different from the person with parental authority, I was sometimes asked, 'What is your relationship to this person?' It was a bit of a hassle to have to explain it every time, and each time I was asked, I was reminded that I was 'different from others.'
Fortunately, I was 15, so I could explain the situation and didn't suffer any strong negative effects. (In the first place, 'leaving the family register with my father' was something I had wanted.) However, I think it wouldn't have been strange to feel unnecessary 'guilt' if I were in my childhood and couldn't explain it well.
The time and money required for procedures are greater than for others
When I applied for a passport as a minor, I needed the consent of the person with parental authority and had my mother sign it, but because our surnames were different, I was told, 'Please submit additional documents to prove the relationship with this person,' and I had to go back home in tears. It ended up costing extra time and money for trips to the passport center and requesting a copy of the family register. It was common for more documents to be required than the information found by searching on the internet. (It gets you into the habit of checking in advance. Haha)
For the reasons above, I felt it was better to keep the 'Family Register' and 'Parental Authority' together, so we decided to have both the 'Family Register' and 'Parental Authority' with my husband.
As of June 2023, it has been a year since our child was born, and I have not had any trouble at all so far because I, the mother, do not hold either the 'Family Register' or 'Parental Authority.' (As mentioned earlier, at daycare and the hospital, I am only called 'So-and-so's mom.' Haha)

So, thank you for waiting.
That is all for the 'What happens? Edition'.
From the next chapter, it is the 'Procedures Edition'.
I would like to introduce the procedures from pregnancy to after childbirth in chronological order.
To summarize first:
・If the Family Register/Parental Authority is with the 'Mother', it is relatively simple as it only involves a notification of birth out of wedlock and hospital confirmation.
・If the Family Register/Parental Authority is with the 'Father', there are more things to do as follows.

That said, I think it is much easier than changing names for bank accounts, driver's licenses, passports, credit cards, etc., which one party has to do in the case of a legal marriage...!
Now, I will explain immediately.
00_Insurance coverage for fertility treatment is OK even for common-law marriage!
From April 2022, fertility treatment became covered by insurance! Moreover, common-law marriage is also eligible!

Until a little while ago, the situation was that 'you had no choice but to register your marriage to get subsidies for fertility treatment,' but now it is possible to undergo treatment while remaining in a common-law marriage.
01_Let's go get the Maternal and Child Health Handbook
Once you are pregnant and the heartbeat is confirmed (around 8 weeks), you go to get the Maternal and Child Health Handbook. I went to the Osaka City Kita Ward Office to get mine.
At that time, you have to fill out various forms, and there was a section to indicate [ Married / Unmarried ] [ Plan to register marriage (around when) / No plan ].
We checked [ Unmarried ] and [ No plan to register marriage ], and as expected, the public health nurse asked us about our situation.
When I told her, "We are a common-law couple with separate surnames," she said, "I see," and the conversation ended smoothly without any further questions.
I think the response varies depending on the local government, but let's hold our heads high...!
02_Let's "acknowledge" the child while still a fetus
This is the procedure mentioned earlier for the father to establish a legal father-child relationship by acknowledging that "this child is my child."
It can be done at either timing, [ During pregnancy / After birth ], but I recommend acknowledging it "during pregnancy."
The reasons are:
① If the husband happens to pass away before the birth, the child's family register will remain "father unknown" for life.
② If the husband happens to pass away before the birth, the right to inherit property will not arise.
③ You cannot write the husband's name in the father's section of the birth registration.
For details, I think the following URL is easy to understand.
https://best-legal.jp/illegitimate-child-apperception-5792/
In the case of fetal acknowledgment, the place of submission is the mother's registered domicile.
When I inquired about the procedure, I received the following response.

Where to submit in case of fetal acknowledgment
Mother's registered domicile
Applicant
Father (can be done by mail in addition to at the counter)
Items to bring (in the case of Asahikawa City)
・Acknowledgment notification
・Personal identification documents
The documents I actually submitted are as follows (I added the date and recipient name after this).
Please check with your local government in advance for other necessary documents.

Less than a week after mailing it, the following documents arrived. I think this depends on the local government.

_
03_Be a little careful when choosing a hospital
Regarding where to give birth, we were looking for a place on the premise that "a partner can be present during birth," but some hospitals had restrictions such as "only the husband on the family register can be present."

In addition to presence during birth, the stance on whether a common-law husband can provide consent for emergency surgery or receive explanations from doctors varies by hospital, so I recommend checking in advance.
04_Submitting a Notification of Separation of Family Register to Streamline Procedures (Optional)
We visited the Osaka City Kita Ward Office twice to ask about procedures after birth. (They were very kind and helpful, thank you!)
During those visits, we were informed that procedures go more smoothly if the "child's place of birth," "mother's registered domicile," and "father's registered domicile" are all in the same municipality.
What this means is... if they are the same, they can be processed right there, but if they are different, they have to be sent back and forth between municipalities by mail, which causes delays.
After the procedures for changing "parental authority" and "family register" are finished, there are still applications for health insurance cards, subsidies for infant medical expenses, and opening bank accounts waiting.
・It is better to get these done as quickly as possible
・It is also smoother to have them in the same place when obtaining family register documents in the future
For these reasons, we decided at this timing to move my registered domicile to the same address as my husband's.
(By the way, if you are legally married, the couple's registered domicile becomes the same at the time of submitting the marriage registration. However, in the case of a common-law marriage, if you do nothing, you remain in your parents' family register. At the time we started living together, we didn't feel any particular need for this, so we left it as it was.)
As for the procedure, we submitted a "Notification of Separation of Family Register." When we inquired about where to submit it, it seems it can be done at the original registered domicile, the new registered domicile, or the place of residence.

The details to be filled in look like this.
To prevent the fetal acknowledgment from being overlooked, it is safer to include a note to that effect in the remarks column.

As a result, at the address of my husband's parents' home,
① Father-in-law (head of household), mother-in-law, husband, younger brother-in-law
② Me (head of household)
These two family registers have been created.
↓ The newly created family register looks like this

Since fetal acknowledgment is not recorded in the family register, it is smoother to check at the counter of the new registered domicile's office before submitting the birth registration, asking, "Has the information regarding fetal acknowledgment been transferred from the old registered domicile to the new one?"
05_Birth registration after the baby is born
You have plenty of time for steps up to 04 as they can be done while you are pregnant, but after the birth, there is a rush of procedures.
The calendar below is an estimate of the schedule for cases where the "family register" and "parental authority" are transferred to the husband, assuming the birth is on June 1st, the birth registration is submitted immediately, and everything goes smoothly.

It takes at least one month to finish all the various procedures. (During this period, the wife has no physical strength to move around after childbirth, so the husband's cooperation is essential!)
Note that while it goes like this if the "registered domicile," "resident record," and "place of procedure" are in the same municipality, it will take a little longer if they are different due to returning to one's parents' home for birth, as there will be more mail procedures between municipalities.
※If you choose to keep the "family register" and "parental authority" with the wife, you only need the fetal acknowledgment notification during pregnancy, and the procedures required after birth are the same as for legally married couples, so I think it will be finished in about half the time.
These are the points to be careful about with the birth registration
・The child will be considered "illegitimate"
・If prenatal acknowledgment has not been filed, the father's section will be blank
・The registered domicile will be the mother's address
・The applicant is the "mother," but anyone can go to the counter
・When submitting, verbally state that prenatal acknowledgment has been filed
The child will be considered "illegitimate"
A child born to a married couple is called a "legitimate child," and a child born to an unmarried couple is called an "illegitimate child." The term "illegitimate child" often carries images of children of mistresses or secret children, and in the past, it was disadvantageous for inheritance, but the Civil Code was amended in 2013, and they no longer suffer disadvantages. Now that "legitimate" and "illegitimate" are just terms, I think you don't need to worry about it too much.
If prenatal acknowledgment has not been filed, the father's section will be blank
If the aforementioned "prenatal acknowledgment" has not been completed, the birth registration will not be accepted unless the father's section is left blank. Personally, I feel that whether or not you can write the father's name is a big deal in terms of feelings. By all means, please file for acknowledgment while the child is still a fetus!
The registered domicile will be the mother's address
Immediately after birth, the child will be entered into the mother's family register, and the content will differ depending on who is currently the head of the family register.
<If the mother is already the head of the family register>
・Enter the mother's registered domicile and the child's name
<If the mother is not the head of the family register>
・Enter the mother's current registered domicile and the name of the head of the family register (often the father or mother)
・Enter the new registered domicile (the family register the mother and child will enter) in the "Other" section *If you are creating a new registered domicile in a different municipality, one copy of the family register transcript is required
The applicant is the "mother," but anyone can go to the counter
The applicant section requires the mother's address, registered domicile, signature, and date of birth.
In the case of an illegitimate child, even if prenatal acknowledgment has been performed, the "father" cannot be listed as the applicant. (If you really want to make it the father, it is possible to submit it not as the father but as a "cohabitant." However, it is said to be troublesome.)
Wait, do I have to go to the government office with a post-partum, exhausted body!? I was surprised for a moment, but as long as the mother has filled out the documents, it is fine for the husband or parents to go to the counter. However, if there are any deficiencies, you cannot correct them on the spot and will have to come back.
When submitting, verbally state that prenatal acknowledgment has been filed
If you verbally state "I have filed for prenatal acknowledgment" at the time of submission, it seems the government office staff can process it more smoothly. After verifying the facts, the staff will record that fact in the "Other" section.
For other details, this URL is informative
https://www.city.kuwana.lg.jp/kosekijyumin/kurashi/todokede/shussei-kakikata.html
↓ Below is the birth registration I actually submitted

Submission location
Child's place of birth OR mother's registered domicile OR mother's registered address
In-person submission
Anyone is fine
Items to bring
・Birth registration (in addition to the hospital's, you can also download it from the internet)
・Maternal and Child Health Handbook
06_Transferring "parental authority" from mother to father via parental authority (management rights) notification
Submit this at the same time as the birth registration. It is not necessary if you want to keep parental authority with the mother. If you are transferring parental authority from the mother to the father, fill it out as follows.

Submission location
"Child's registered domicile" or "Applicant's registered domicile or registered address or temporary residence"
Applicant
Father or mother exercising parental authority
In-person submission
Anyone is fine
Items to bring
・Parental authority (management rights) notification
・Family register full certificate *Not required if submitting to the registered domicile
07_Child allowance is changed after application
Depending on the municipality and income, this is a system where you can receive 15,000 yen per month. You must apply within 15 days of birth. If you miss the deadline, you will lose one month's worth, so I think it is best to apply for this first without waiting for other changes to be finished, and then perform the name change procedures later.
You apply where your resident record is, so in our case, it was Osaka City. Basically, I think the procedure is done at the counter or by mail, but surprisingly, Osaka City allows online procedures if you have a My Number card...! (Here)
Submission location
Municipal office where the person with parental authority has their resident record
Applicant
Person with parental authority
*Basically, the spouse with the higher annual income becomes the applicant and recipient, but in the case of separate surnames, the "person with parental authority" is the father in this case since the submission of 06_Parental Authority Notification is complete.
Items to bring (in the case of Osaka City)
・My Number card
・Health insurance card of the person with parental authority
・Something that can confirm the bank account number of the person with parental authority (passbook, cash card, etc.)
By the way... the "Child Rearing Allowance" paid to single-parent households is not applicable to common-law couples with separate surnames. At first glance, looking only at the family register, it looks like a single-parent household, but since they are in the same household on the resident record, they are considered to be sharing a livelihood and are not treated as a single-parent household.
08_Request a family register transcript for the father and child
This is the request for the family register transcripts that will be used in the next step, '09_Petition for Permission to Change Child's Surname'.
What you need is:
1. Father's family register (all items certificate) (The head of the household does not have to be the person themselves)
2. Child's family register (all items certificate) (This will be the mother and child's family register)
The '1. Father's family register' can be obtained even before birth, but the '2. Child's family register' cannot be requested until at least 1 to 3 business days have passed after submitting the birth registration and parental authority notification. (If the place where the birth registration is submitted, the mother's registered domicile, and the father's registered domicile are different, it may take a little longer.)
Depending on the municipality, some allow you to request them at convenience stores using your My Number card (unfortunately, at the time, Sapporo City only accepted requests at the counter or by mail).
Also, when a couple in a common-law relationship requests the family register transcript of their spouse (unregistered), a power of attorney is required.
Where to request (each)
・Registered domicile of mother and child
・Registered domicile of father
Who can request
The person themselves or a direct blood relative (grandparents, parents, children, grandchildren, etc.)
Items to bring
・Family register certificate request form (available at the municipal office counter)
・Personal identification documents
・Power of attorney
09_Petition to the court for 'Permission to Change Child's Surname'
This is the procedure to apply to the court to 'change the child's surname' and receive a permission document (= Certificate of Permission to Change Surname).
It takes about one week to ten days from the application until the permission document arrives.


Where to file
Family Court with jurisdiction over the child's place of residence
* Since it is 'where the child actually is,' it is okay if it is different from the resident registration (e.g., at the mother's parents' home). Therefore, the address here is where the child is physically located.
Reason for petition
In this case, select 'Father's acknowledgment' and enter the date of acknowledgment. (In our case, it was immediately after the pregnancy was discovered, so November 5, Reiwa 3).
Applicant
Person with parental authority (Since '06_Submission of Parental Authority Notification' is complete, in this case, the father)
Required documents
・Petition for Permission to Change Child's Surname
・Child's family register (all items certificate)
・Father's family register (all items certificate)
・Seal of the person with parental authority
・Revenue stamp 800 yen
・Postage stamps for communication (84 yen)
10_Transfer 'family register' from mother to father via entry notification
Once the '09_Petition for Permission to Change Child's Surname' is successfully completed, the court will mail the 'Certificate of Permission to Change Surname' to your home, so take that to the municipal office!

After it is accepted, it will change as follows in as little as 1 to 3 business days. However, if the 'place where the procedure was performed,' the 'registered domicile,' and the 'resident registration' are in different locations, it will take about one week to ten days because mail exchanges between municipalities will be added.
Before
1. Mother (head of household), child
2. Father-in-law (head of household), mother-in-law, father (= husband), brother-in-law
After
1. Mother (head of household)
2. Father-in-law (head of household), mother-in-law, brother-in-law
3. Father (head of household), child
↓ The notation on the family register will look like this

11_Finally, issuance of the child's health insurance card
After coming this far, we can finally get the child's health insurance card issued!
Of course, you could apply immediately after birth and then go through the name change procedure once the "change of child's surname" is complete, but that would be double the work, so we waited until this point to apply.
However, a point to note is that until the child's health insurance card is issued and the "12_Application for Medical Expense Subsidy for Infants" is completed, you will have to pay 100% of the child's medical expenses out of pocket. Therefore, if you want to minimize out-of-pocket payments, I think it is better to apply immediately after birth and then apply for the change later.
The issued child's health insurance card will be used for the "12_Medical Expense Subsidy for Infants" procedure that follows.
Where to file
For company employees or civil servants: The health insurance of your employer
For self-employed individuals: National Health Insurance
Applicant
The spouse with the higher annual income
Items to bring *The following is for my husband's company
・Health Insurance Dependent (Change) Notification
・Child's Family Register (Koseki) Certificate
・Certificate of Residence for all household members
・Withholding tax slips for both spouses
12_Application for Medical Expense Subsidy for Infants
This is a system provided by each local government to "subsidize a portion of children's hospital expenses." Since conditions and required documents vary by municipality, please check in advance before applying.
In the case of Osaka City, you can apply online from here.
Where to submit
The municipal office where the person with parental authority has their certificate of residence
Applicant
Person with parental authority (the same person receiving the child allowance)
*Basically, the spouse with the higher income is the applicant, but in the case of separate surnames, it is the "person with parental authority"
Items to bring (for Osaka City)
・Child's health insurance card
・Applicant's health insurance card
・Identification documents for the applicant's spouse
Depending on the municipality, there may be a guideline stating "within 1 month of birth." However, that is just guidance so that you can use the subsidy at the 1-month checkup; unlike child allowance, you can still get a refund later even if the deadline has passed.
[Summary] If it's just marriage, common-law is easier; if a child is born, it's tough
That's it! Thank you for your hard work.
It feels like a lot, but about half of these procedures are necessary even for legal marriages, regardless of common-law status.
Also, if you keep the "family register" and "parental authority" with the mother, the only necessary procedure is "acknowledgment," so I don't think the burden is that great.
Even if you transfer the "family register" and "parental authority" to the father, the procedures only need to be done at the municipal office and the court, so I think it is definitely easier than the name changes for My Number, driver's license, bank accounts, cards, etc., that one party is forced to do in a legal marriage.

In summary...
Marriage case, common-law is easier.
If common-law:
・Put your certificate of residence in the same household
・Create a common-law marriage contract (optional)
If legal marriage:
・Submit marriage registration
・Put your certificate of residence in the same household
・One party changes the name on their My Number, driver's license, bank account, and credit card
After the child's birth procedures,
if you keep the "family register" and "parental authority" with the
"mother", it is relatively easy.
If you transfer it to the "father": It's a bit tough. (Still much better than name changes for legal marriage)
I think that is the result.
For now, it is best to prepare a power of attorney.
In our case, we changed the 'family register' and 'parental authority' to the father, and the father is also planning to mainly handle the procedures after birth, so we needed relatively few powers of attorney, but you never know when or where they will be needed. I think it is safe to prepare plenty of powers of attorney just in case.
Sample power of attorney for use at the municipal office
Sample power of attorney for use in procedures related to a child's birth
Thank you for reading until the end.
I started writing this note on May 28, 2022.
After that, I made additions and corrections on June 6, 2023.
In this note, I have summarized the results of my own research and questions I asked by visiting the municipal office. However, this is just our case, and I think there may be cases where the response differs depending on the local government. Please check with your registered domicile or the local government where you live for detailed procedures.
If you have something you don't understand, something you want to ask, or want to consult a little,
please feel free to contact me at
・Twitter: @mary_trip_trip
・facebook: Marie Outake outake.mary
please contact me.
Even if you are not in trouble, if this was helpful, please leave a comment saying 'It was helpful!'. It will make me happy.
However, regarding consultations, I am an amateur, so there is no guarantee that it is absolutely correct.
If I don't know something, I will say I don't know.
Also, if I am busy, I might forget to reply.
If you are okay with that, please feel free to...!!!
PS.
I am currently studying for the Administrative Scrivener examination in November 2023, so if I pass, I hope to be able to support more people as an Administrative Scrivener. I will do my best!!!
Added on January 31, 2024
I passed the 2023 Administrative Scrivener examination. If you have any consultations regarding common-law marriage or contract creation, please feel free to contact me~~~
https://lit.link/outakemary
Added on September 27, 2024
By completing the procedure for listing your former surname on your certificate of residence before applying for your My Number Card,
Kusakabe [Otake] Torakichi
you can create a card with this notation. It doesn't necessarily change anything, but if you would like to do so, by all means! I already created my My Number Card, so I am eagerly awaiting the right time to switch it over!


I hope you can live a life where you cherish the things that are important to you.

