Patent Divisional Applications in Japan: When You Can Divide, How to Use Them, Fees and Translations (2026)

"The examiner has allowed claims 1–5 but refused claims 6–10. Can we get the allowed claims granted now and keep fighting for the rest?" "We received a decision to grant, but our competitor's product falls outside the claims. Is it too late?" "Our parent application was filed in English — does a divisional need a new translation?"

A divisional application (bunkatsu shutsugan) lets you carve out part of the inventions disclosed in a pending Japanese patent application and pursue them in a new application that keeps the original filing date. Used well, it is one of the most flexible tools in Japanese patent prosecution. Used too late, it is simply unavailable — the timing windows under Article 44 of the Patent Act are strict.

In this article, Japanese Patent Attorney Toru Kano of BrandAgent explains when a Japanese application can be divided, the substantive requirements, common strategic uses, the official JPO fees, and what foreign applicants should know about translations and deadlines.

*Information as of November 2026. Check the latest rules on the JPO website.

Foreign applicants act through a Japanese patent attorney

An applicant with no domicile or business office in Japan cannot deal with the JPO directly. Filing a divisional application, requesting its examination and responding to Office Actions must all be done through a representative in Japan — in practice a licensed Japanese patent attorney (Benrishi). At BrandAgent, every case is handled personally by the patent attorney, and we communicate in English and Chinese. Payment by PayPal (in JPY) or bank transfer is accepted.

What is a divisional application?

Under Article 44 of the Patent Act, an applicant can divide a patent application containing two or more inventions and file part of them as one or more new applications. If the requirements are met, the new application is treated as filed on the filing date of the original (parent) application. This means:

• Novelty and inventive step are judged as of the parent's filing date (or its priority date), not the date you actually file the divisional.
• The patent term is not extended: the JPO's guidelines state that, where the substantive requirements are met, the parent's filing date is treated as the filing date, and the term ends 20 years from that date (Art. 67(1)).
• A divisional can itself be divided again (a "grandchild" application), as long as each generation meets the requirements.

When can you divide? The three windows

According to Article 44(1) and the JPO Examination Guidelines, a divisional can be filed only in these periods:

The 30-day window after grant: watch the registration fee

The 30-day window is not available for a decision to grant issued in reconsideration by the examiner before appeal, or after an appeal decision has remanded the case. More importantly, the patent is registered when the first registration (annuity) fee is paid, and from that moment the application is no longer pending. The JPO therefore recommends dividing on or before the day you file the fee payment. If the payment period is extended, the 30-day window is deemed extended accordingly (Art. 44(5)).

The 3-month window after refusal: overseas applicants

The window after a decision of refusal runs from the first decision of refusal; a second refusal issued after an appeal remand does not open a new window. Under Article 44(6), if the period for requesting an appeal against the refusal is extended under Article 4, the divisional window is deemed extended by the same period.

This matters for overseas applicants. For patent appeals against a decision of refusal, the JPO extends the appeal period for applicants residing abroad (zaigaisha) by one month ex officio — 3 months plus 1 month. In practice, an overseas applicant usually has up to 4 months from service of the decision of refusal to decide on both an appeal and a divisional. Always have your Japanese attorney confirm the exact date for your case.

Substantive requirements

The JPO examines whether a divisional is valid. In summary:

• Not everything: the divisional must not claim all of the inventions in the parent (in practice this is rarely an issue).
• Within the parent as filed: the content of the divisional must be within what was disclosed in the parent's original description, claims and drawings — tested like a new-matter check for amendments.
• Within the parent just before division: the content must also be within the parent's description, claims and drawings immediately before the division.

If the substantive requirements are not met, the divisional loses the parent's filing date and is examined as of its actual filing date — usually fatal, because the parent's own publication then becomes prior art. The examiner may ask for an explanation of where the divisional's claims are supported in the parent. Filing a short statement with the divisional explaining the changes and their basis makes examination smoother.

Strategic uses

1. Get allowed claims granted now, keep fighting for the rest

If only some claims are refused, you can delete the refused claims from the parent and obtain a patent quickly, while moving the refused subject matter to a divisional and continuing to argue (or amending differently). This is useful when you need an enforceable right soon — for licensing, investors or a competitor already on the market.

2. Keep a family pending

A pending divisional lets you adjust claims later to cover competitors' products or new embodiments that appear after the parent is granted. A post-grant divisional (window 2) is the last chance to do this for that parent.

3. Respond to a final refusal

After a decision of refusal, you can request an appeal, file a divisional with amended claims, or both. A divisional filed on the same day as the appeal request is generally treated as filed at the same time as the appeal. Choosing between appeal and divisional depends on whether the examiner's reasoning can be overcome by argument or only by narrowing the claims.

4. Cover other embodiments or unity issues

If the examiner raises lack of unity, or the description contains embodiments that the current claims do not cover, a divisional lets you claim them without losing the original date.

Pitfalls to avoid

• The Article 50-2 notice: if the divisional receives the same reason for refusal that was already notified in the parent (and you could have known it before requesting examination), the examiner adds an Article 50-2 notice. Your amendments are then restricted as if a final notice of reasons for refusal had been issued. Do not simply re-file the same refused claims.
• Double patenting: if the divisional claims the same invention as the parent after division, it can be refused under Article 39. The claims must be genuinely different.
• Separate examination request: a divisional is not examined automatically. Its examination must be requested within 3 years from the parent's filing date — or, if that has already passed, within 30 days from the divisional's filing date.
• Missed windows cannot be fixed: after registration, or after the refusal window closes without an appeal, the parent can no longer be divided.

Official JPO fees

A divisional is a new application, so the ordinary fees apply again (JPO fee table, November 2026):

*For applications filed on or before 31 March 2019, the examination fee table is lower (118,000 + 4,000 per claim). For a divisional in an older family, confirm which table applies before paying. Annuities for a divisional granted later are paid like any other patent. Attorney fees depend on the work involved — ask for a free quote.

Because the examination fee is charged again in full, keep the number of claims in a divisional focused. A divisional with a few well-chosen claims is often more effective — and cheaper — than one that copies all the parent's claims.

Translations for foreign applicants

A divisional can be filed as a foreign-language application (for example in English), with a Japanese translation filed later. The normal translation deadline is 1 year and 4 months from the filing date (or the earliest priority date). Because a divisional's deemed filing date is usually much earlier, the JPO allows the translation for a divisional to be filed within 2 months from the divisional's actual filing date even after the normal period has passed. If the translation is missing, the JPO sends a notice; if it is still not filed, the application is deemed withdrawn.

In practice, when the parent already has a Japanese text, it is usually faster and safer to file the divisional directly in Japanese, based on the parent's Japanese text. This also makes it easier to show that the divisional's content is within the parent as filed.

FAQ

• Q. Can we divide after the patent has been registered?
  A. No. A divisional requires the parent to be pending. After a decision to grant, divide within 30 days and before the registration fee is paid.
• Q. Does a divisional get a new 20-year term?
  A. No. If the requirements are met, it is treated as filed on the parent's filing date, and its term ends 20 years from that date.
• Q. How long do overseas applicants have after a decision of refusal?
  A. The window is 3 months from service, extended in line with any extension of the appeal period. For overseas residents the JPO extends the patent appeal period by one month ex officio, so usually 4 months in total.
• Q. Do we need to request examination of the divisional?
  A. Yes, within 3 years from the parent's filing date, or within 30 days from filing the divisional if that period has already passed.
• Q. Can we communicate in English or Chinese?
  A. Yes. Every case is handled personally by the Japanese patent attorney, in English or Chinese.