In Japan, the national phase application must be filed within 30 months from the priority date (the 30-month deadline).
According to the Japanese patent law, a PCT application can be entered into the Japanese national phase without a Japanese translation. Then, there is the two-month deadline after the entry of the Japanese national phase for filing a Japanese translation. Please note that the translation filing due is two months from the date of the entry, not two months from the 30-month deadline.
Further, it is not mandatory to file a translation of amendments to PCT Articles 19 and 34 with the Japan Patent Office. But if these amendments do exist in your case, the applicant must notify the Japanese patent attorney in a written form whether these amendments should be filed or not.
If the applicant is uncertain whether to file a request for examination of the Japanese application, we recommend that the applicant not file the translation of the amendments at the time of the Japanese national phase entry to reduce the cost. The translation can be filed with the request for examination, or the amendments can be directly filed to match a claim granted in the U.S. without filing the translation for the amendment under PCT Article 19 or 34.
The claim for examination can be filed within three years from the international application date.