How long is the protection period of Japanese invention patent application

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 Once the original patent application is converted, it will be deemed withdrawn.

yes. Within 3 years from the date of application, or within 3 months from the date of receipt of the rejection decision, the patent type can be changed from design to invention/utility model at the request of the applicant.

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 Once the original patent application is converted, it will be deemed withdrawn.

yes. Multiple designs may be included in one design application.

• Grant fee: The applicant shall pay the granted fee within 30 days after receiving the granted notice.
• Annuity: The annual fee for the first to third years must be paid together with the application fee when the patent application is filed, and the annual fee will be paid year by year from the fourth year, and the payment period corresponds to the granted date. 200% of the year's annual fee paid within the month is a late fee.

• via Paris Convention : 6 months from earliest priority date.
• Hague Agreement route: 6 months from earliest priority date.

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.

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

1-2 years

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