The Japan Patent Office (JPO) requires that patent applications in Japan must be filled out in Japanese. Furthermore, the title of each document and the headings of each document must also be written in Japanese. While the actual description, claims and drawings may be originally submitted in English, the JPO will require Japanese translations to be submitted within one year and two months from the earlier of either the filing date or the priority date. If the translations are not submitted, the application is deemed withdrawn.
Furthermore, the JPO requires the applicant to appoint a legal representative in Japan as part of the application process. For applicants applying from abroad, this legal representative will usually be their Japanese attorney, although the legal representative can be anyone residing in Japan. However, even for applicants applying from within Japan, the JPO still strongly recommends appointing a Japanese patent attorney as your representative as it greatly increases your chances of filing an application correctly.
If you have any questions about patent law in Japan, please contact our office for a legal consultation.