A non-resident individual director or shareholder needs a signature certificate (サイン証明), and a Ministry of Justice (法務省) notice from June 28, 2016 allows it to be authenticated by an official in that person's country of residence, not only the home country. A foreign company acting as a parent entity needs a different document, an affidavit (宣誓供述書), which has no residence-country shortcut: it must be authenticated by a home-country notary or by the home country's consul stationed in Japan.
Do I Need a Signature Certificate or a Corporate Affidavit?
The answer depends on whether the person named in the Japan filing is an individual or a company. An individual foreign director or shareholder signing in their personal capacity, for example a KK founder confirming their own signature on registration paperwork, uses a signature certificate (サイン証明). A foreign company itself, most commonly where that company sits as the representative member (代表社員) of a Japanese godo kaisha (合同会社) or as the parent behind a foreign company Japan branch, uses a corporate affidavit (宣誓供述書) instead.
These are not two labels for the same document. They are two different instruments that satisfy different requirements at the Legal Affairs Bureau (法務局), the authority that examines and accepts the registration filing, and each carries its own rule for where it can be authenticated. Confusing them is the most common way a non-resident founder submits a document the Legal Affairs Bureau (法務局) will reject on form, not substance. The complete incorporation guide for non-residents covers where this document sits inside the wider filing sequence.
What Is the Authentication Rule for an Individual's Signature Certificate?
An individual's signature certificate can be authenticated either in the person's home country or, since the 2016 Ministry of Justice (法務省) notice, in that person's country of residence. The practical effect is that a founder does not always need to return to their country of citizenship to get this document notarized.
The internal example that illustrates this well: a US national living in China can have their signature certificate authenticated by a US consul stationed in China, rather than needing to reach a US consul or notary inside the United States itself. Before the 2016 relaxation, the country-of-residence route was not reliably available for this document. Founders relocating ahead of incorporation, or living long-term outside their country of nationality, benefit most directly from this rule.
What Is the Authentication Rule for a Foreign Company's Affidavit?
A foreign corporate parent's affidavit has no residence-country exception, and this is the rule non-resident founders most often get wrong by assuming the individual's rule carries over. The affidavit (宣誓供述書) must be authenticated either by a notary in the company's own home country, or by that home country's consul stationed in Japan (日本駐在の本国領事).
A third country's consular mission is generally not a workable substitute, because many consular posts limit their notarial acts to documents intended for use in their own home country and will decline to notarize a document destined for a Japan filing. This means the choice of which consulate to approach is not interchangeable the way it can be for an individual's signature certificate: the mission has to be either in the company's own home jurisdiction, or that same country's post physically located in Japan. Founders structuring a Japan entity around a foreign holding company, including the funding patterns discussed in this piece on GK capital from a transfer-restricted jurisdiction, should confirm the affidavit route early, since it sits on the incorporation critical path.
Can the Affidavit Be Notarized Remotely, Without Travel?
Yes, in some jurisdictions, but only if the notary performing the act is properly commissioned in the company's own home country. Several jurisdictions permit live-video notarization of an affidavit even where general notarial acts still require physical presence, and the resulting document can then go through that country's apostille process.
Japan is a party to the Hague Apostille Convention, so a validly apostilled affidavit is accepted without further legalization once it reaches the Legal Affairs Bureau (法務局). The trap to avoid is using an online notarization platform commissioned in the wrong jurisdiction: a remote-online-notarization act performed by a notary licensed in a country other than the founder's home country does not satisfy the home-country-notary requirement, even if that act is later apostilled. The controlling fact is which jurisdiction commissioned the notary, not whether the signing happened by video.
Key points:
(a) An individual foreign director or shareholder's signature certificate (サイン証明) can be authenticated in either the home country or, since June 2016, the person's country of residence. (b) A foreign company's affidavit (宣誓供述書) for a Japan registration matter must be authenticated by a home-country notary or by that home country's consul stationed in Japan, with no residence-country substitute. (c) A remote or apostilled notarization only satisfies the affidavit rule if the notary who performed the act was commissioned in the company's own home jurisdiction, not merely in whichever country the signer happened to be sitting in.
Who Handles the Filing and Who Arranges the Documents?
The founder or the company's own counsel arranges the underlying notarization or affidavit through a notary, consulate, or legal counsel in the relevant home jurisdiction, and Aplash takes that authenticated, translated document and carries the Japan-side filing through to the Legal Affairs Bureau (法務局). This division keeps the reserved acts, notarizing a foreign document and filing it with a Japanese registry, with the professionals licensed to perform them in each jurisdiction.
For founders weighing a KK against a GK structure, or comparing this document burden against the cost of the whole filing, the formation cost guide and the startup formation guide lay out the fuller sequence these documents fit into. Founders ready to move from the paperwork question to an actual filing plan can review Aplash's company setup service for how the Japan-side registration work is scoped.
Frequently Asked Questions
I am a foreign individual director living outside my home country. Can I use a notary where I currently live instead of traveling home?
Often yes. Since a June 2016 Ministry of Justice (法務省) notice, a signature certificate (サイン証明) can be authenticated by an official in your country of residence, not only in your country of nationality. The internal example used in practice is a US national in China using a US consul stationed in China, so confirm the same logic applies to your specific nationality and residence country before relying on it.
My foreign company is the representative member of a Japanese GK. Can our home country's embassy in a third country notarize the affidavit?
Generally no. A foreign company's affidavit (宣誓供述書) must be authenticated by a notary in the company's home country or by that home country's consul stationed in Japan; many consular missions in third countries only notarize documents intended for use in their own home jurisdiction and will decline a document destined for a Japan filing.
Does Aplash arrange the notarization or apostille of our parent company's documents?
Aplash's role is the Japan-side registration filing with the Legal Affairs Bureau (法務局). The founder or the parent company arranges the affidavit's notarization, apostille where applicable, and certified translation independently through their own legal counsel or a notary or consulate in their home jurisdiction, and Aplash then works from that completed document.
Conclusion
The signature certificate and the corporate affidavit look similar on the surface but answer to different rules: one gained a residence-country option in 2016, the other never had one and still requires a home-country notary or that country's consul in Japan. Getting the authenticator right the first time avoids a rejection round-trip at the Legal Affairs Bureau (法務局) and keeps a non-resident founder's filing timeline intact.
This article is informational only and does not constitute legal, tax, or regulatory advice. Consult a qualified advisor before acting on the content. Last updated: August 2026.