Electronic signatures in Japan: the Electronic Signatures Act, hanko and cloud signing

Japan has a long tradition of the personal seal, the hanko or inkan, and for years it was common to stamp contracts even when nobody strictly required it. Since around 2020, businesses and the government have moved quickly away from paper and seals, and electronic contracts (denshi keiyaku) are now part of everyday business. This guide explains the legal basis and where the limits are.

For a comparison with other countries, see our e-signature legality overview and the guide Are electronic signatures legal around the world?.

Are electronic signatures legal in Japan?#

Yes, for most contracts. Under the Civil Code, a contract is generally formed when the parties agree, without any particular form, unless a law says otherwise. A seal or handwritten signature is therefore not usually what makes a contract valid; it matters mainly as evidence.

The Act on Electronic Signatures and Certification Business (Act No. 102 of 2000) supports electronic contracting in two ways:

• Definition. An electronic signature is a measure applied to electronic information that shows the information was created by the person who applied it and makes it possible to confirm whether the information has been altered.
• Presumption of authenticity. An electronic record is presumed to have been genuinely made when it carries the person's own electronic signature of a kind that only that person can create by properly managing the necessary codes or devices. This mirrors the presumption Japanese civil procedure gives to paper documents bearing a person's signature or seal.

Types of electronic signatures recognised#

In practice, people in Japan talk about two models:

• Signer-based signatures (tōjisha-gata). Each signer uses their own electronic certificate, sometimes issued under the Act's accredited certification business scheme.
• Provider-based or "witness" signatures (jigyōsha shomei-gata or tachiainin-gata). The signer confirms their intent through a cloud service, typically after email or other authentication, and the service applies its own technical signature or seal to the document.

In 2020 the relevant ministries published Q&A guidance indicating that provider-based services can, depending on how they work, fall within the Act's definition of an electronic signature, and that in some cases, for example with sufficiently strong identity checks, they may also support the presumption of authenticity. Whether a particular process meets that test depends on the facts.

Signkoi works in a way similar to the provider-based model: signers confirm their intent in the browser, and Signkoi seals the finished PDF. It doesn't issue personal electronic certificates or signatures under the accredited certification scheme, and whether a particular use meets the Act's tests depends on the facts.

Documents that often still need wet ink, a notary or a certified signature#

The list has been getting shorter, especially after the digital reform laws of 2021, but some documents still need a particular form:

• Contracts that must be made as a notarial deed (kōsei shōsho), such as fixed-term land leases for business use and voluntary guardianship contracts.
• Documents that a specific law still requires on paper, or allows electronically only with the recipient's prior consent. Check the rules for your sector, such as real estate, finance or subcontracting.
• Filings with courts and government bodies, which follow their own procedures.

On stamp duty (inshizei), it is widely understood that electronic contracts, which create no paper document, aren't subject to it. Confirm with a tax adviser for your situation.

Collecting good evidence with simple e-signatures#

With a provider-based signature, the strength of your position comes from the process and its records: who signed, how they were identified and whether the document has changed. With Signkoi, every completed document includes:

• A deliberate signing step. Each signer draws, types or uploads a signature and agrees to sign electronically.
• A sealed PDF. A tamper-evident seal and a trusted timestamp make later changes detectable.
• An audit trail. Sending, opening and signing events are logged with times, IP addresses and browser details, and summarised in a certificate of completion.
• Optional identity checks. Ask signers to enter an access code you share separately, or a one-time code sent to their email. For important contracts, using an extra check like this is a sensible step.
• Independent verification. Anyone holding the PDF can check it at signkoi.com/verify.

Keep the signed PDF and certificate of completion as part of your records, and check any retention rules that apply to you, such as those for tax records.

How to send a document for signature in Japan with Signkoi#

1. Upload your PDF, or start from a template.
2. Add your signers and set a signing order, for example to mirror your internal approval flow.
3. Place signature and other fields for each signer.
4. Set reminders, an expiry date and an access code or email one-time code.
5. Send. Recipients sign in their browser with no account, and Signkoi's interface is available in Japanese, among 12 languages.
6. Download the sealed PDF and certificate of completion.

Frequently asked questions#

Do I still need a hanko on a contract?#

Usually not. Most contracts are valid without a seal. A seal has mainly served as evidence that the document is genuine, a role that an electronic signature and its records can play for electronic contracts.

Is a cloud-based signature covered by the Electronic Signatures Act?#

It can be. Government guidance from 2020 indicates that provider-based services may fall within the Act, depending on how they confirm the signer's intent and identity. Whether the presumption of authenticity applies depends on the specific process.

Can every contract be signed electronically?#

No. Contracts that must be made as a notarial deed, and documents that a specific law still requires on paper, need their own procedure.

Not legal advice#

This guide is general information, not legal advice. Laws and official guidance change, and using Signkoi doesn't guarantee that a particular signature will be valid or enforceable in your situation. For important or regulated documents, talk to a qualified Japanese lawyer (bengoshi).