Expanded Japanese Grace Period for Non-Japanese Applicants

By Sara Rosengard and Taro Yaguchi
*Note: A newer article published in February 2017, summarizing the content below, is available here.

Requirements Then and Now:

Patent applications have to be filed before a prior art disclosure. But what if the disclosure is the inventor’s own? Can he lose novelty against his own invention? The Exception to Lack of Novelty of Invention, as stipulated in Japanese Patent Act Article 30, treats inventions published by the inventor or the right holder as still having novelty so long as certain requirements are met. This law prevents the accidental loss of patenting rights for inventors who disclose their invention, in print publication or otherwise, before filing patent applications.

The Japanese grace period for a pre-filing disclosure is six months. Compared to the U.S.’s one year, that duration is short. But, prior to 2012, the biggest difference was that the exceptions only applied to an overly restrictive set of circumstances, which made it particularly difficult for non-Japanese applicants to qualify for the grace period.

The most anachronistic requirement was that the disclosures had to be made at JPO Commissioner-designated World Fairs. Never mind that World Fairs are held so infrequently that any innovation would be rendered irrelevant by the time they rolled around! If World Fairs were not feasible, then one would have had to present at JPO or local government-sponsored conferences. With such limited restrictions, is it any surprise that many non-Japanese applicants gave up on preserving their patenting rights in Japan?

That was then. Now, as of April 2012, an amendment has been put in place where almost all disclosures are covered by the provision, provided that they were made by the inventor or the right holder. As such, the six-month safe harbor now applies to disclosures made at study meetings and academic conferences both in and out of Japan regardless of JPO designations, as well as to inventions divulged during TV presentations, or sales activities, among other circumstances.


Japan’s novelty grace period cannot be claimed without proper filing. In order not to lose your right to obtain a patent in Japan, the following procedures must be followed:
1. You can file for a Japanese grace period within six months from the time of disclosure in one of two ways:

      a. by filing an application directly with the JPO, or
      b. by filing an International Patent Cooperation Treaty (PCT) application designating Japan.

    Note: When filing under (b), the applicant must include a statement stating the circumstances of the disclosure in the appropriate section of the PCT application form.

    2. Enter into the Japanese PCT national phase within 30 months after filing the PCT International application.

    3. File a written “Certificate of Proof of Disclosure” within 30-days from the time of entering the PCT Japan national phase.

    There are many who think that filing a priority national application and then filing a Japanese or PCT application at a later date as usual will qualify them for protection. Nothing could be further from the truth. Even if claiming a convention priority based on a non-Japanese application, which has been filed within six months from the presentation, you will still need to apply for an International PCT and request for the grace period within the six-months window from the time of that disclosure.

    There are many advantages for utilizing the novelty grace period. If you wish to discuss the benefits of claiming this provision, please contact a Keisen attorney for more information.

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