Applicants may want to file an Amendment to a Japanese patent application for a variety of reasons. However, it is important to be aware of the deadline when an amendment has to reach the Japan Patent Office (JPO).

By when do we need to file a Voluntary Amendment to have the JPO examiner consider it? What may we change?

It is simplest to file a Voluntary Amendment with or before the Request for Examination of a patent application in Japan. However, you may also file Voluntary Amendments after the Request for Examination is filed, as long as substantive examination by the Japan Patent Office (JPO) has not commenced. Within that time frame, you are free to amend as you wish as long as amendments are grounded on the original claims, specification, or drawings.

Please be aware that once a JPO examiner has begun the substantive examination process, even if you submit a Voluntary Amendment, it might not be considered. It is possible to have a Japanese patent agent check with the JPO for its estimated (but non-binding) examination commencement period (not precise date) for a particular case. If there is still time before the examination will begin, you might want to file a Voluntary Amendment even after submitting the Request for Examination. Note that any change in subject matter must take place before examination.

How does a Non-Final Office Action change the deadline and allowable changes for an Amendment?

If a Non-Final Office Action has been issued, then the due date of the amendment would be dictated by the JPO examiner in the Office Action. However, as per Art. 17-2 of the Patent Act, acceptable Amendments are restricted and subject matter may not be changed.

Since a Final Office Action will limit allowed amendments' scope further and Notice of Allowance can shut the window of opportunity to file an amendment, it is important not to put off an amendment once the Request for Examination has been filed. It may be wise to consult a Japanese patent attorney concerning specific cases.


Translated Article 17 of "Patent Act." Japanese Law Translation.
Japan Patent Act, original text. E-Gov. Effective May 30, 2017.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.