Which is the competent authority for utility model patent applications in Japan?

yes.

• Within the period of 9 years and 6 months from the date of application for the invention patent, or within 3 months from the date of receipt of the notification of rejection, the patent type of the invention patent may be changed from invention to utility model/design upon request
• A request to change the patent type from invention to utility model/design can be filed within three months from the date of the JPO’s first decision to reject the application

A conversion fee shall be paid for patent type conversion. Once the original patent application is converted, it will be deemed withdrawn.

Inventors have a novelty grace period of 12 months after disclosure (including sale).

25 years

Reinstatement of priority is accepted on grounds of "due care."

yes

The JPO conducts formality examination and substantive examination of invention patent applications. The applicant should submit a request for substantive examination within 3 years from the filing date. The JPO makes an granted decision if it determines after review that no grounds for refusal have been found.

Inventors have a novelty grace period of 12 months after disclosure (including sale).

yes

• Grant fee: The applicant should pay the granted fee and the annual fee for the first year within 30 days after receiving the granted notice.
• Annuity: The annual fee shall be paid year by year from the second year from the date of granted, and the payment of the annual fee may be postponed within 6 months if the annual fee is overdue, but a 200% penalty shall be paid at the same time.

The design does not lose its novelty if it is disclosed by the designer in Japan within 12 months from the filing date/priority date.