Japanese Grace Period Will Be Extended to 12 Months

By: Jonathan Osha and Shinya Kimura


The Japan Diet on May 23, 2018 enacted legislation to extend the novelty grace period for patents in Japan from 6 to 12 months.  The revised patent law will be applied to patent applications filed on or after June 9, 2018.

While this is an improvement for those who may wish to rely on the grace period, it is important to note that the grace period of 6 months still applies to a disclosure made on or before December 8, 2017.  Further, the grace period in Japan does not apply to a foreign priority application (such as a U.S. patent application), and either a PCT application or a domestic Japanese application should be filed within the grace period.

Therefore if, for example, an inventor makes a pre-filing disclosure in the United States, relies on the one-year U.S. grace period to file a U.S. utility patent application, and then enters Japan directly or via PCT based on a later filing within the one-year Paris Convention window, the Japanese grace period may not apply and the Japanese patent would be barred by the pre-filing disclosure.

Please also note that this amendment simply extends the length of the grace period and other requirements for applying the Japanese grace period are unchanged.  For example, unlike the U.S. grace period, “Proof of Disclosure” should be submitted within 30 days from the filing date (or from the date of entering the Japanese national phase).

The same revision was made to Japanese design law.