All foreign languages became acceptable for patent filings in Japan

The Japanese Patent Law Regulation was revised on March 25, 2016 and the revised Regulation became effective on April 1, 2016.
According to Article 25quater of the revised Regulation, any foreign language is acceptable when filing a foreign language application with the Japan Patent Office (“JPO”).

Previous Regulation:

The JPO only accepted foreign language applications that were in English. Other foreign languages were not accepted.

Revised Regulation:

In addition to English language, any other foreign language may be used for filing a patent application with the JPO. For example, patent applications in German, Korean, French, or Chinese are now accepted by the JPO.
Therefore, if there is insufficient time to prepare a Japanese language specification and claims for your Japanese patent filing, you can use the original language specification and claims for filing a Japanese national patent application in the JPO claiming priority under the Paris Convention to the original patent application(s) filed in your country.
A Japanese translation must be submitted to the JPO within 16 months from the earliest priority date.

The revised regulation is not applied to PCT national entry applications into Japan and foreign language version is not acceptable for PCT entry applications. However, when entering a PCT international application into Japan, we only have to file a notice of entry (in Japanese) within 30 months from the earliest priority date, without Japanese translations of specification, claims, or drawings. The Japanese translations of specification, claims, and drawings have to be submitted within two months from the date of filing the notice of entry.

If you have any questions about these revisions, please let us know.