Content-certified mail (内容証明郵便, naiyō shōmei yūbin) is a uniquely Japanese postal service in which Japan Post (日本郵便) officially certifies who sent what document, and on what date. Unlike ordinary certified or registered mail in the US or UK, which only proves that something was delivered, this service proves the exact wording of the letter itself: Japan Post retains an identical certified copy on file. For an overseas owner of Japanese rental property, it is the standard first formal step when a rent demand or a notice of contract termination has to be put beyond any later dispute about who said what. This guide walks through how to draft and send content-certified mail, following the primary information published by Japan Post, including the fee schedule after the October 2024 revision, the strict formatting rules, and how the tool is actually used in real estate.
Key points of this article
- Content-certified mail proves the "wording" and the "date of sending and delivery" of a document; it does not prove that the contents of what you wrote are legally correct.
- Over the counter (paper), one page of content plus delivery certification totals 1,420 yen (approx. $9 USD; rough estimate at about 155 JPY/USD as of July 2026); e-Nyoshomei (the electronic version) is 1,645 yen (approx. $11 USD) under the same conditions (after the October 2024 revision).
- The format is written vertically with upper limits such as "20 characters per line and 26 lines per page," while e-Nyoshomei allows documents of up to five pages created in Word.
- Even if the recipient refuses to accept delivery, if they obstructed delivery without a legitimate reason it may be deemed to have "arrived" (Article 97 of the Civil Code, 民法 Minpō).
- For rent-arrears demands or rent negotiations, having the property management company or a specialist review the wording before sending makes it easier to move on to the next procedure.
What is content-certified mail? The basics to grasp before drafting
Content-certified mail is a system in which the post office certifies the content and date of a document that has been sent. What is certified, however, is the fact that "this exact text was sent on this day," not whether the assertions written in it are legally valid. This distinction has no direct equivalent in most Western postal systems, where a "certified" or "recorded" service confirms only handling and receipt, never the letter's wording; understanding it keeps your purpose for sending content-certified mail from drifting.
It is easier to organize if you divide the objects of certification into three broad categories: the date of sending, the content of the document, and the fact of delivery. Of these, the fact of delivery is only recorded once you add "delivery certification" (配達証明, haitatsu shōmei), described later, which is the closest Japanese counterpart to a return-receipt service abroad. Note that content-certified mail alone does not certify when the item arrived.
What content-certified mail "does" and "does not" prove
| Item | Proven by content-certified mail | Not proven |
|---|---|---|
| Date of sending | Yes — the post office records the date of dispatch | — |
| Content of the document | Yes — the post office keeps a certified copy of the identical text | Whether the described content is true or justified |
| Fact of delivery | Conditional — proven only if delivery certification is added | On its own, does not prove the delivery date or receipt |
| Whether the recipient read it | — | No — opening and reading in full are outside the scope |
In other words, content-certified mail is a tool for locking in the fact that "a claim or notice was certainly sent, on this day, in this exact wording." It is sometimes used for the psychological effect it has on the other party, but its true value lies in leaving an objective record that can be used in later negotiations or procedures. For an international investor, this is the Japanese market's answer to the question of how you create admissible, dated evidence without immediately involving a lawyer.
Typical situations where property owners use it
In rental management, content-certified mail appears when verbal or email exchanges have reached a dead end. For example, the case of a tenant whose rent is several months in arrears and who does not respond even to reminder phone calls, to whom you send a letter clearly stating the payment deadline and advance notice of contract termination. In our own experience on the management front line, it is not unusual for the other party's behavior to change once the written letter arrives. For the full picture of arrears handling, please also refer to What are countermeasures against rent arrears? Occurrence cases, response flow, and prohibited actions.
How much does content-certified mail cost? Comparing the counter and e-Nyoshomei
To state the conclusion first, to send one page of content with delivery certification, the guideline is a total of 1,420 yen (approx. $9 USD) at the post office counter and 1,645 yen (approx. $11 USD) via e-Nyoshomei, the internet-based electronic version (both after the October 1, 2024 postage revision, assuming no express delivery). The more pages you add, the more likely e-Nyoshomei becomes the cheaper option, while for a single page the counter comes out lower.
On current competing sites and older articles you will see figures such as "about 1,220 yen (approx. $8 USD) at the counter, about 1,470 yen (approx. $9 USD) electronic," but these are pre-revision numbers. Because standard-size mail and special-handling fees were raised in October 2024, it is best to review with the latest breakdown. All figures below are rough USD estimates at about 155 JPY/USD as of July 2026 and will shift with the exchange rate.
Fee breakdown at the counter (paper)
When sending over the counter at the post office, the fee per page of content builds up as follows. When a document runs to two or more pages, the content-certification fee is added at 290 yen (approx. $1.90 USD) per additional page.
- Postage (standard size, within 50g): 110 yen (approx. $0.70 USD)
- General registered-mail fee: 480 yen (approx. $3 USD)
- Content-certification fee (first page): 480 yen (approx. $3 USD) (each subsequent page +290 yen / approx. $1.90 USD)
- Subtotal (without delivery certification): 1,070 yen (approx. $7 USD)
- Delivery-certification fee: +350 yen (approx. $2.30 USD) → total 1,420 yen (approx. $9 USD)
Fee breakdown for e-Nyoshomei (electronic)
e-Nyoshomei (e内容証明) is a service in which you upload a document created in Word over the internet, and the post office's system automatically handles printing, verification, and stuffing and sealing the envelope. The fee items are finely divided, but the total per page is roughly as follows.
- Postage: 110 yen (approx. $0.70 USD)
- Electronic-mail fee: 19 yen (approx. $0.12 USD) (pages 2 to 5, 6 yen / approx. $0.04 USD each)
- Content-certification fee: 382 yen (approx. $2.50 USD) (pages 2 to 5, 360 yen / approx. $2.30 USD each)
- Certified-copy delivery fee: 304 yen (approx. $2 USD) (bulk delivery, up to 100 addressees: 503 yen / approx. $3.20 USD)
- General registered-mail fee: 480 yen (approx. $3 USD)
- Subtotal (without delivery certification): 1,295 yen (approx. $8 USD)
- Delivery-certification fee: +350 yen (approx. $2.30 USD) → total 1,645 yen (approx. $11 USD)
Comparison table: counter vs. e-Nyoshomei
| Comparison item | Post office counter (paper) | e-Nyoshomei (electronic) |
|---|---|---|
| Total fee (1 page, with delivery certification) | Approx. 1,420 yen (approx. $9 USD) | Approx. 1,645 yen (approx. $11 USD) |
| Total fee (1 page, without delivery certification) | Approx. 1,070 yen (approx. $7 USD) | Approx. 1,295 yen (approx. $8 USD) |
| Surcharge from the second page (content-certification fee) | +290 yen / page (approx. $1.90 USD) | +360 yen / page (approx. $2.30 USD) |
| Method of creation | Handwriting or PC both allowed | Word (2016/2019/2021, M365 desktop version) |
| Page limit per document | No page limit | Up to 5 pages |
| Reception hours | Business hours of the counter at a collection-and-delivery post office | 24 hours (excluding maintenance windows) |
| What to prepare | 1 original + 2 certified copies, and a personal seal | Word file and a credit card etc. for payment |
| Sealing and keiin (binding seal) | Correction seal and binding seal required | Not needed (electronic processing) |
If one page is enough and there is a handling post office nearby, the counter is convenient. e-Nyoshomei suits conditions such as a long document, difficulty visiting a counter on weekdays, or sending the same text to multiple recipients. The sources are the fee tables at Japan Post (日本郵便), "Delivery Certification" and Japan Post (日本郵便), "e-Nyoshomei (Electronic Content-Certified Mail)" (after the October 2024 revision).
Format rules and how to write content-certified mail
If you break the format rules, content-certified mail will not be accepted at the counter. Especially when sending over the counter (paper), there are upper limits on the number of characters per line and the number of lines per page. This character-counting discipline is distinctly Japanese and has no parallel in Western registered-letter services, where wording and layout are entirely up to the sender; first, grasp the whole picture with the quick-reference table.
Quick reference for characters and lines
| Paper orientation | Characters per line | Lines per page |
|---|---|---|
| Vertical writing | Within 20 characters | Within 26 lines |
| Horizontal writing (pattern 1) | Within 20 characters | Within 26 lines |
| Horizontal writing (pattern 2) | Within 13 characters | Within 40 lines |
| Horizontal writing (pattern 3) | Within 26 characters | Within 20 lines |
Horizontal writing can be chosen from three patterns. When creating on a PC, setting the characters-per-line and line count of your word processor within these limits prevents having to redo the document. For e-Nyoshomei, page and margin rules are set separately, and roughly 1,584 characters per page (the standard setting of 10.5-point Mincho typeface with single-line spacing) is treated as the guideline.
How characters are counted and which characters can be used
Character counting has its own rules. Note the points that are easy to misunderstand.
- A symbol is counted as one character each.
- Brackets are counted as one character for the top and bottom (or left and right in horizontal writing) as a whole.
- Characters enclosed in a circle or square are counted by summing each character and the frame (a mark indicating sequence is counted as one character overall).
- When emphasis dots or underlines are added, the whole including the dots or underline is counted as one character.
The usable characters are kana, kanji, numerals, brackets, punctuation marks, and things generally used as symbols. Roman letters may be used only for proper nouns. Writing amounts and dates clearly in numerals and avoiding ambiguous expressions makes it easier to cite the content later.
How to write the keiin (binding seal), corrections, and sender and recipient
Paper documents sent over the counter have their own etiquette around sealing. Getting this wrong tends to mean re-creating the document, so check before sending. Note that this reliance on a personal seal (印鑑, inkan) is itself a Japanese custom; the return-receipt letter familiar to Western readers requires no such stamping.
- Keiin (binding seal): When a document runs to two or more pages, a binding seal is stamped across the seam (if there is only one sender, a clear mark such as a "binding seal" notation is also acceptable).
- Corrections: If you make a writing error, cross it out with a double line etc., note the number of characters and the location in the margin at the side or end, and stamp the sender's seal. Keep the corrected characters legible.
- Sender and recipient: Names and addresses are appended in the margin at the end (this may be omitted if already stated in the body; the appended portion is not counted toward the character and page totals).
Even when using a Word format distributed as a "content-certified mail template," confirm before sending that it complies with these character/line and sealing rules. A template is only a foundation; the substance of the wording must be rewritten to fit your own case. Details of the format can be confirmed at Japan Post (日本郵便), "Content-Certified Mail: Conditions of Use, etc.".
How to send content-certified mail | Procedures for the counter and e-Nyoshomei
Once the format is in order, sending is not difficult. Because the flow differs between the counter and e-Nyoshomei, check the procedure for each.
Procedure for sending at the post office counter
- Prepare three copies of the same text (1 original to send to the recipient, 1 certified copy kept by the post office, 1 certified copy retained by the sender).
- If two or more pages, stamp the binding seal, and on the envelope write the sender's and recipient's addresses and names with the same content as the document.
- Bring the item, unsealed, to the counter of a collection-and-delivery post office etc. that handles content-certified mail.
- State at the counter whether to add delivery certification, and pay the fee.
- Keep the sender's copy and the receipts for the registered mail and delivery certification.
Procedure for sending by e-Nyoshomei
- Log in to e-Nyoshomei on Web Yubin (Web Post), and upload the document file created in Word.
- Enter the sender's and recipient's information, and select options such as delivery certification.
- When you make payment by credit card etc. following the on-screen prompts, the post office side automatically handles printing, verification, and dispatch.
- After dispatch, you can check the dispatch details and delivery status on the system.
With either method, keep the sender's copy and the receipt on hand. When a demand or negotiation drags on, they become primary materials showing the fact of sending. If you are uneasy about crafting the wording, one option is to consult a partner experienced in practical work, referring to How to choose a reliable rental property management company. For an overseas owner who cannot easily reach a Japanese counter, the 24-hour e-Nyoshomei route combined with a local management partner is often the most practical setup.
How to use content-certified mail in real estate transactions, and points of caution
On the real estate front line, take care that sending content-certified mail does not become "the goal in itself." What matters is leaving a record that connects to subsequent negotiation or legal procedures, at the appropriate timing. Whether to also use delivery certification is a judgment that varies by situation.
Whether to combine delivery certification, by use case
| Use case | Content certification | Combine delivery certification | Aim |
|---|---|---|---|
| Demand / dunning for rent arrears | Recommended | Strongly recommended | Record the payment deadline and advance notice of termination, with an arrival date |
| Notice of contract termination / cancellation | Recommended | Strongly recommended | Leave a record of "when" the manifestation of intent to terminate arrived |
| Request to increase or decrease rent | Recommended | Recommended | Fix the request date as the starting point for negotiation or conciliation |
| Request for deposit return / restoration to original state | Depending on circumstances | Recommended | Clarify the fact and timing of the request |
| Request for eviction (surrender of premises) | Depending on circumstances | Recommended | Record the assertion of just cause and the timing of notice |
Delivery certification is the combination that makes the effect of content-certified mail useful in practice. Especially for rent-arrears demands and contract terminations, "when it arrived" can become the starting point for later procedures, so combining it gives peace of mind. Regarding increases and decreases in rent, reading Rent reduction guidelines and how landlords should respond to equipment failures together will help you grasp how to structure a request.
What happens if the recipient refuses to accept it?
Even if it comes back due to refusal of receipt or absence, the notice is not necessarily void. Under the Civil Code, a manifestation of intent takes effect from the time it reaches the other party (the "arrival principle," 到達主義 tōtatsu-shugi, which differs from the "mailbox rule" familiar in some common-law systems where dispatch can suffice), and it is provided that when the other party obstructs arrival without a legitimate reason, it is deemed to have arrived at the time it would normally have arrived (Article 97, paragraphs 1 and 2, of the Civil Code). The text can be confirmed at the Civil Code on e-Gov Law Search (e-Gov法令検索).
That said, whether refusal of receipt is treated as "arrival" as such is judged differently case by case according to the circumstances. Generally, sending with delivery certification and keeping records such as the returned envelope and the absence-notice slip becomes material to support a later assertion. When stepping into surrender of premises, checking The flow of eviction requests and notices to tenants for just cause and how to advance negotiations makes the judgment easier.
Content-certified mail is a means of leaving a record of transparent, honest exchanges. Wording that conveys facts calmly, rather than emotional pressure, comes closer to a resolution without damaging long-term trust. When you are unsure about the wording or how to proceed, please also make use of a review of your management company or INA's free consultation.
Frequently Asked Questions (FAQ)
Q. In what situations do you use content-certified mail?
You use it in situations where you later want to prove that you "sent it / it arrived," such as demands for rent arrears, notices of contract termination or cancellation, requests to increase or decrease rent, and requests for deposit returns. The guideline is the stage where verbal or email negotiations have reached a dead end and you want to leave a definite record.
Q. Does content-certified mail alone have legal binding force?
Content-certified mail itself has no power to compel payment. What is proven is the fact that "this exact text was sent on this day," not that the content of the claim is correct. Compulsory execution requires separate procedures such as litigation or a demand for payment. This is an important contrast for foreign investors accustomed to systems where a formal demand letter carries more direct weight.
Q. If the recipient refuses to accept it, is the notice void?
It is not necessarily void. If they obstructed delivery without a legitimate reason, it may be deemed to have arrived at the time it should normally have arrived (Article 97 of the Civil Code). Sending with delivery certification and keeping the return record supports an assertion about arrival.
Q. Which is cheaper, e-Nyoshomei or the counter?
For just one page, the counter (with delivery certification, about 1,420 yen / approx. $9 USD) is cheaper, and e-Nyoshomei is about 1,645 yen (approx. $11 USD). However, as the number of pages increases the difference narrows, and when sending the same text to multiple recipients or when it is hard to visit a counter on weekdays, e-Nyoshomei, which can be sent 24 hours a day, is convenient.
Q. Is it better to hire a lawyer?
If the content is complex, or if it is likely to develop into legal procedures such as litigation or surrender of premises, consider consulting a specialist. Because the expression of the wording can affect later procedures, coordinating with a management company or lawyer from the demand or termination-notice stage gives peace of mind.
