In spring 2018, Japan implemented a Revision to Unfair Competition Prevention Act that includes a change to the disclosure grace period (exception to lack of novelty of invention period) for filers of Japanese patent, utility model, or industrial design applications. Instead of the short 6-month grace period as under the old law, a 1-year grace period will soon be used, from December 8, 2018.

Please note that the grace period changes based on the application date to Japan. To receive the longer grace period's benefits, a patent application needs be filed on or after June 9, 2018 in Japan or in a PCT application designating Japan, and later enter the Japanese national phase.

If your application is one of the latter PCT-Japan cases, the international application's filing date is the basis for determining the grace period of disclosure before application. (A PCT application filed on or before June 8, 2018 after disclosure can be protected from loss of novelty of invention only up to six months post-disclosure.) However, the earliest the invention may have been disclosed and still receive the exception is December 9, 2017.

If the applicant files the PCT application between June 9 and December 8, 2018, he or she may claim an exception to lack of novelty for a disclosure on or after December 9, 2017. (During this period, the grace period is being extended day by day, toward the full one-year period.) All applications filed on or after December 9, 2018 may receive the benefit of a maximum one-year's grace period on disclosure.

For more details on the procedures and qualifications for an invention to be protected from prior disclosure by the inventor or someone who knew of the invention from the inventor, please see " our Q&A article on patent application grace periods for non-Japanese inventors."


Japan Patent Office. "発明の新規性喪失の例外期間が6か月から1年に延長されます [The exception to lack of novelty of invention period is to be extended from 6 months to 1 year]," May 30, 2018.

________. June 2018 version of handbook for disclosure-application grace period.

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.