How long is the protection period of Japanese invention patent application

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

• 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.

yes.

• Within 3 years from the filing date, the patent type can be changed from utility model to invention upon request of the applicant
• Utility model patents can be converted to design patents at any time

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 Once the original patent application is converted, it will be deemed withdrawn.

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

yes

25 years

• Inventions under the via Paris Convention : 12 months from the earliest priority date.
• via Nationalization of PCT inventions: 30 months from the earliest priority date.

10 years

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