Japanese patent law is based on the first-to-file principle and is mainly given force by the of Japan. Article 2 defines an invention as "the highly advanced creation of technical ideas utilizing the law of nature".
English translation
The definitive version of Japanese law is the text in the Japanese language. An official English-language translation of the law does not exist, but the Ministry of Justice Japan has the website "Japanese Law Translation", where one can search for Japanese laws and their unofficial English translation. Intellectual property (IP) laws such as Patent Act, Copyright Act, Trademark Act, Design Act and Unfair Competition Prevention Act are included there.
In addition, the Industrial Property Digital Library (IPDL) offers public access to IP Gazettes of the Japan Patent Office (JPO) free of charge through the Internet.
Reliable information on Japanese IP law in English is also provided by the websites of Intellectual Property High Court, Japan Patent Office, "Transparency of Japanese Law Project", European Patent Office, and Institute of Intellectual Property (IIP) of Japan. For more details, see "External links" at the bottom of this page.
Definition of invention
Article 2, paragraph 1, of the Patent Act of Japan defines invention as "the highly advanced creation of technical ideas by which a law of nature is utilized". This definition was introduced in 1959 following German jurist Josef Kohler's definition. Although the substance of the definition is almost accepted, there is opposition against giving a definition of "invention" in a written law (in many other patent systems, invention is not defined directly).
In the generally accepted interpretation, the phrase highly advanced does not imply a requirement for an inventive step since the matter of inventive step is dealt with in Article 29, paragraph 2. The definition may have been included in light of the Utility Model Act of Japan which gives a definition of a device as "the creation of technical ideas by which a law of nature is utilized".
Patent prosecution
The procedures for obtaining a patent right in Japan are described in detail on the website of Japan Patent Office. The patent prosecution procedure under Japanese law is similar to that in most other patent systems. Article 39 states that a person who is the first to file an application for a patent for an invention may obtain that patent, rather than a different person who is the first to invent the same invention.
A patent may be granted for an invention if: the invention as claimed is industrially applicable (Article 29, paragraph 1), the claims are novel (Article 29, paragraph 1), the claims are inventive (Article 29, paragraph 2), the patent does not harm public order, morality or public health (Article 32), amendments to the specification, claims or drawings remain within the scope of the features disclosed in the original version (Article 17bis), the specification discloses the invention in a manner sufficiently clear and complete for a person skilled in the art to carry it out (Article 36, paragraph 4), the statement of the claims is clear (Article 36, paragraph 6), the application meets the requirement for unity of invention (Article 37), the applicant is the first to file an application for a patent for the invention (Articles 29bis and 39), and the applicant has the right to obtain a patent for the invention (Article 25 and 38, and Article 49, paragraph 7). (This is a summary; Article 49 contains a full list of conditions.)
Article 30 provides a six-month grace period for disclosures made through an experiment, publication, presentation at a study meeting or an exhibition (a trade fair or the World's Fair) or for if the invention becomes known to public against the applicant's will. Such disclosures do not form part of the prior art. This is a much broader exemption than the one available under European patent law () but is significantly narrower than that provided under United States patent law.
Application
A person desiring to obtain a patent has to submit a request, specification, claims, any drawings necessary, and the abstract to the commissioner of the Japan Patent Office (Article 36). Article 36bis allows an application in foreign languages (currently only in English) if the applicant submits a Japanese translation within two months from the filing date. However, the applicant may not amend the foreign language file (Article 17, paragraph 2). In 2007 there was a revision of Japan Patent Law. Pursuant to a 2007 revision of the law, the period for filing a Japanese translation for a Foreign Language Application is 14 months from the filing date or the priority date.