Keisen’s Recommendations For Filing an Information Disclosure Statement (IDS) in Japan

The Japan Patent Office (JPO) has implemented an information disclosure system whereby applicants have a duty to disclose prior art that they know of at the time of filing a patent application. However, the requirement is not widely recognized so that many applicants do not follow it. This is because negligence of the duty to disclose prior art in practice has no effect on the validity of the patent, unlike the Information Disclosure Statement (IDS) in the USPTO.
This sort of strategy, however, may come back to haunt you, particularly if the subject Japanese patent is involved in a U.S. licensing arbitration. One possibility is that the arbiter may find the patentee’s behavior less than equitable, and determine the patent unenforceable on moral and ethical grounds. There may be other pitfalls. Whatever the case may be, the important thing is to guard oneself against potential problems. We therefore highly recommend that everyone involved in the preparation of the application comply fully with the disclosure system. The details of the requirements are as follows:

I. Information Disclosure System in Japan

A. Overview

The prior art information disclosure system was introduced in September 2002.
All patent applications filed after September 2002 are required to disclose the prior art information.
However, the effect of a violation is so minimal that an application once patented will not become invalidated.

B. The IDS requirement applies to the following applications:

*All Japanese domestic applications and all international applications filed after September 1, 2002.
*In case of a PCT application entering into the Japanese national phase, an IDS system is required only for applications whose international filing date falls after September 1, 2002.
*In case of a divisional application, an IDS system is required if the parent application was filed after September 1, 2002.

C. Methods for the information disclosure

*At least one publication should be listed in “Background” section of a patent specification.
*Only publication or literature is acceptable, including electronically formatted Web documents available online.
*If an applicant has a number of prior arts, an applicant can disclose only the major ones that are most relevant.
*If a prior art is a patent publication, the following information has to be provided: its application number, publication number or patent number.
*For a non-patent publication, including a dissertation, a thesis or any kind of electronically formatted non-patent document, the following information is required: the name of the document, name of the organization published, publisher, date of presentation, published date, volume, number, cited page number(s), and/or URL address and online published date.
*An applicant does not have to submit the original or duplicate copies of publications. However, depending on the case, the examiner sometimes asks for the documents for examination purposes. Only in this case, an applicant is required to submit copies of publications about prior arts.
*If there are no prior arts to disclose, an applicant must state the reason in the patent specification.

D. Effects of Disclosure

*If a specification does not include any information on prior arts nor a reason for not including the prior arts, an official action will be issued from the JPO. Upon receiving the official action, the applicant can file an amendment according to the examiner’s request.
*Failure in disclosure could result in the rejection by examiners but will not invalidate the patent after issued. In other words, negligence of the duty has no effect on the validity of the patent right.
*Therefore, even if the fact that a patentee, who had known the availability of the prior arts relevant to the invention in question, did not disclose the prior art information is discovered after a patent is obtained, there is no legal effect on the issued patent.
*However, a patentee knowingly neglecting to follow this system may face indirect disadvantages when attempting to enforce his/her rights.
The details of the JPO’s new guidelines are also available in English on the JPO’s website (
Finally, we would like to request that you create a list of references/documents and provide that to us along with your instructions to file a Request for Examination.

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