Japanese patent law is based on the first-to-file principle and is mainly given force by the Patent Act. The administrative procedure for obtaining a patent in Japan is similar to that of most other patent systems, and includes the examination of novelty, inventive step and industrial application of the invention.

In general, a patent application for an invention should be filed at the patent office before the invention has been revealed to the public, because otherwise the disclosure to the public is considered as an opposable “prior art”. As such it will be taken into account by the patent office examiner when considering whether the claimed invention meets the requirements of novelty and inventive step. If an invention is available to the public prior the filing date of the patent, the patent office will refuse to grant the corresponding patent based on lack of novelty or inventive step.

In Vietnam, the Novelty of inventions is regulated at the Article 60 of Vietnamese IP Law as follows:

Article 60. Novelty of inventions

1/ An invention shall be considered as novel if it is not publicly disclosed by use or means of a written or oral description or any other form, inside or outside the country, before the filing date or the priority date, as applicable, of the invention registration application.
2/ An invention shall be considered as not yet publicly disclosed if it is known to only a limited number of persons who are obliged to keep it secret.
3/ An invention shall not be considered as lacking of novelty if it was published in the following circumstances, provided that the invention registration application is filed within 6 months from the date of publication:
a) It was published by another person without permission of the person having the right to registration as provided for in Article 86 of this Law;
b) It was published in the form of a scientific presentation by the person having the right to registration as provided for in Article 86 of this Law;
c) It was exhibited at a national exhibition of Vietnam or at an official or officially recognized international exhibition by the person having the right to registration as provided for in Article 86 of this Law.

The Japan Patent Office has now decided to extend the grace period in Japan from six to 12 months for patent and utility models. The revised law will become effective on 9 June 2018, and will apply to disclosures made on or after 9 December 2017.

Thus, for all inventions published as of 9 December 2017, the 12-month grace period will apply. For example, if an invention has been made available to the public on 24 January 2018, the disclosure will not be considered if the corresponding patent application is filed on or before 24 January 2019.