Debt Collection by Content-Certified Mail in Japan｜Effect, Contents and Timing

The invoice is long overdue, telephone calls go unanswered and emails are ignored. In Japan the first formal step at this point is almost always a demand sent by content-certified mail (naiyo-shomei yubin). The device exists nowhere else, and its effect is widely misunderstood: some creditors expect far too much of it, and others send it at precisely the moment when it does most harm. What follows is an explanation, under Japanese law, of what the letter does, what it must contain, and what should be considered before and after it is sent.

Contents

What content-certified mail actually certifies
What the letter should state
The legal effect
Why the letter is sent in a lawyer’s name
What to consider before sending
What happens afterwards
In closing
How to contact us

What content-certified mail actually certifies

Content-certified mail is a postal service under which Japan Post certifies, from a copy retained in its own files, who sent what text, to whom and on what date. Because no equivalent exists in most other countries, overseas creditors often misread it. Note carefully what is certified and what is not: the service proves the wording of the letter and the date of posting, but it does not prove that the letter reached the addressee, still less that the demand is well founded in substantive law. For that reason a certificate of delivery (haitatsu-shomei) should always be requested at the same time, so that the Post Office also certifies the date of delivery; without it, proving receipt of the demand in later proceedings becomes unnecessarily difficult. The letter must comply with limits on characters per line and lines per page, and an electronic version can be sent online.

What the letter should state

The parties — the names and addresses of the creditor and the debtor, and, where a lawyer sends it, the fact that the lawyer has been instructed.
The origin of the claim — the date and subject matter of the contract, the date of delivery or completion of the work, invoice numbers: enough to identify the claim beyond argument.
The amount — principal, sums already received, and the date from which and the rate at which delay interest runs.
The deadline and the manner of payment — commonly one to two weeks from delivery, with the remittance account stated.
The steps to be taken in default — civil litigation, a demand for payment (shiharai-tokusoku), provisional attachment, compulsory execution. Threats going beyond lawful procedure — telling the debtor that its customers will be informed, or that the debt will be published online — must never appear: they achieve nothing and may themselves amount to extortion or defamation.

The legal effect

Under the Civil Code of Japan, a demand postpones the completion of prescription for six months from the date of the demand. Where a claim is close to being time-barred, a letter sent by content-certified mail therefore buys six months. It buys nothing more: unless, within those six months, an action is filed, a demand for payment or civil conciliation is applied for, or a provisional attachment is obtained, the postponement lapses, and a further demand made during the period of postponement has no additional effect. By contrast, an acknowledgement of the debt in writing, or a part payment, renews prescription, which then begins to run afresh.

Where the addressee prevents delivery without justification, the Civil Code treats the notice as having arrived at the time when it would ordinarily have arrived. Even so, the same text is in practice sent by a second method as well, so that the point need not be argued later.

Why the letter is sent in a lawyer’s name

A demand from the creditor and a demand from the creditor’s lawyer have identical legal effect; their practical effect is not comparable. First, the debtor learns that the creditor has instructed counsel and now has litigation and execution genuinely in view; the file is frequently passed to the debtor’s own legal department or lawyer, and the question shifts from whether to pay to how. Second, communications are channelled through a single point, and the debtor can no longer apply pressure directly to the creditor’s staff. Third, the claim, the calculation and the procedural warning are expressed in terms that are legally accurate and that will not later contradict the creditor’s own pleadings.

What to consider before sending

The letter should not invariably come first. A demand tells the debtor that the creditor is now in earnest, and a debtor inclined to conceal or dispose of assets may respond by emptying its bank accounts, mortgaging its real property or transferring it away. Where other creditors have already levied execution, where the business has ceased trading, or where principal assets are already being disposed of, the sounder course is to obtain a provisional attachment (kari-sashiosae) first and to send the demand once the attachment has taken effect — a sequence that is possible precisely because an application for provisional attachment is heard and granted without notice to the debtor. Conversely, where the debtor has no assets at all, neither a demand nor an action will recover anything, and an investigation of the debtor’s means should precede any decision to pursue the claim.

What happens afterwards

If payment is made by the deadline, the matter ends there. If the debtor asks to pay by instalments, the terms should be recorded in an agreement stating each instalment, an acceleration clause and, where appropriate, a joint and several guarantee; for larger sums, the agreement is best executed as a notarial deed containing an express acceptance of compulsory execution, which gives the creditor an enforceable title without any action at all. If there is no response, or the existence of the debt is disputed, the matter should move promptly to a demand for payment or to civil litigation. Repeating demands for months without entering any procedure merely allows the prescription risk and the risk of asset dissipation to grow together.

In closing

Content-certified mail carries no coercive force of its own. Its value lies in creating an unanswerable record of the demand and in making the steps that follow it visibly real to the debtor. When to send it — and whether to secure the assets before doing so — depends on what the debtor still owns. Instructions may be given from abroad by email and video conference, and we are equally glad to work through the creditor’s own counsel.

How to contact us

Telephone 03-6435-8418 within Japan, or +81-3-6435-8418 from overseas. Lines are open from 08:00 to 24:00 Japan time, including Saturdays, Sundays and public holidays. Enquiries are also received at any hour through the form on this site.

M&A Partners Law Office LPC　Katsuhiro Tsuchiya, Representative Attorney-at-Law (Tokyo Bar Association, Registration No. 26775)　17F Mori Trust Shiroyama Trust Tower, 4-3-1 Toranomon, Minato-ku, Tokyo, Japan

This article is a general explanation based on the laws and practice of Japan as at August 2026 (Reiwa 8). The outcome of any particular matter depends on its own facts, and no specific result is guaranteed.

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