How Is Novelty (Article 29(1) of the Patent Act) Assessed for Patent Applications in Japan?

Novelty (新規性 - shinki-sei) is a bedrock principle of patent law worldwide, and Japan is no exception. Article 29(1) of the Japanese Patent Act mandates that for an invention to be patentable, it must be new. This means that, before the effective filing date of the patent application, the invention must not have been publicly available through various forms of disclosure, whether in Japan or any foreign country. The assessment of novelty is a critical step in the patent examination process and a frequent point of contention in patent validity disputes.

Understanding how novelty is evaluated involves looking at how the claimed invention is defined, what types of prior disclosures are considered novelty-destroying, and what limited exceptions might exist if a disclosure has occurred.

The Broader Framework: Novelty within the Patentability Assessment

In Japanese patent practice, the assessment of novelty typically follows an initial step of defining the scope of the invention for which protection is sought and precedes the evaluation of inventive step. The general procedural flow is:

1. Determining the "Gist of the Invention" (発明の要旨認定 - hatsumei no yōshi nintei): Before comparing an invention to the prior art, its own scope and essential features must be clearly defined. This is primarily based on the language of the patent claims, interpreted with reference to the detailed description in the specification and any drawings. The Supreme Court decision of March 8, 1991 (Minshu Vol. 45, No. 3, p. 123, the "Lipase" case or 「トリグリセリドの測定方法」事件), established that while claim language is paramount, the specification can be consulted, particularly if the claim language is ambiguous or contains obvious errors. There's a growing convergence in practice to apply a consistent claim interpretation methodology across both patentability assessments and infringement litigation.
2. Comparison with Prior Art for Novelty: Once the "gist" of the claimed invention is ascertained, it is meticulously compared with individual prior art references to determine if the invention, as claimed, was already disclosed.
3. Assessment of Inventive Step: If the invention is found to be novel (i.e., not identically disclosed in any single prior art reference), it is then assessed for inventive step (non-obviousness) under Article 29(2).

This article focuses on the second step: the novelty assessment.

Identifying Identical Points and Differences (一致点・相違点の認定)

The core of the novelty examination involves comparing the claimed invention with prior art disclosures. The invention is typically broken down into its constituent elements or features as defined in the claims. Each element is then compared against what is disclosed in a single prior art reference.

• If a single prior art reference discloses all elements of the claimed invention, arranged in the same way to achieve the same result, the invention lacks novelty.
• The comparison should not involve combining multiple prior art references to arrive at the claimed invention; that is the domain of inventive step assessment.
• When dissecting the invention into elements, it's important to consider the technical significance of these elements in the context of the invention as a whole, rather than engaging in overly fine "atomization" that ignores the functional interplay between parts (as suggested by the IP High Court, October 28, 2010, 2010 (Gyo-ke) 10064, the "Coated Belt Substrate" case or 「被覆ベルト用基材」事件).
• Genus-Species and Range Limitations: If a claimed invention represents a broader concept (a genus) and a prior art reference discloses a specific embodiment falling within that genus (a species), the claimed genus invention generally lacks novelty over the disclosed species, as it encompasses something already known. Conversely, if the prior art discloses a broad genus and the claim is directed to a specific, previously undisclosed species within that genus, the species claim might be novel. However, it could still lack inventive step unless the selection of that species leads to an unexpected or advantageous effect (this is characteristic of "selection inventions"). Similar principles apply to numerical range limitations in claims. If a claimed range overlaps with or is broader than a disclosed range, novelty issues arise.

Statutory Grounds for Loss of Novelty (Article 29(1))

Article 29(1) of the Patent Act enumerates three categories of disclosures that, if occurring before the patent application's effective filing date (i.e., the actual filing date or an earlier priority date), will destroy the novelty of an invention. These disclosures can be made anywhere in the world ("in Japan or a foreign country").

1. Publicly Known Inventions (公然知られた発明 - kōzen shirareta hatsumei) - Article 29(1)(i)

This refers to an invention that has become known to an unspecified segment of the public such that its technical content is accessible. This is often referred to as kōchi (公知) in its narrow sense.

• "Content Leakage" Type (内容漏知型 - naiyō rōchi gata): This typically involves situations where information about the invention has been communicated to others.
  • No Obligation of Confidentiality: If the invention's details are disclosed to a third party who is not under an express or implied obligation of confidentiality, novelty is generally lost. It's not strictly necessary for the third party to have actually understood the invention; the fact that it was made accessible to them without restriction is often sufficient.
  • Effect of Confidentiality: Conversely, disclosure under a clear obligation of secrecy does not destroy novelty. This can be an explicit confidentiality agreement or an implied obligation arising from the circumstances of the disclosure (e.g., disclosures during confidential business negotiations aimed at commercializing the invention, or disclosures to employees bound by general duties of confidentiality). The Supreme Court decision of September 11, 1928 (Minshu Vol. 7, No. 10, p. 749, the "Rotary Sieve for Drying" case or 「乾燥用旋回座網」事件) held that even without an express secrecy agreement, if an invention was shown to a few individuals for purposes like seeking funding or sales assistance with the understanding that it was for a potential patent, an implied duty of confidentiality could be recognized, preserving novelty.

2. Publicly Worked Inventions (公然実施をされた発明 - kōzen jisshi o sareta hatsumei) - Article 29(1)(ii)

This pertains to situations where the invention has been put into practice in a way that its technical content could have been understood by an unspecified member of the public. This is often referred to as kōyō (公用).

• Location of Working: Public working can occur not only in plainly public places but also on private premises, such as within a factory, if adequate measures are not taken to maintain secrecy from individuals who have access (e.g., visitors, contractors) and are not bound by confidentiality. The key is accessibility to the invention's technical details. The number of people who actually observed the working is not as crucial as the fact that it was openly workable or observable (IP High Court, April 10, 2003, 2001 (Gyo-ke) 264, the "Kaki Mochi Dough Manufacturing Device" case or 「かき餅生地の製造装置」事件).
• Secret Commercial Use: If an invention (e.g., a manufacturing process) is used commercially but is kept as a trade secret and its details cannot be discerned from any publicly available products, such secret use typically does not destroy the novelty of the process itself or of product features that cannot be reverse-engineered.
• Sale or Distribution of Products Embodying the Invention: Generally, making products embodying the invention available to the public through sale or distribution constitutes public working and destroys novelty for the features discernible from those products.
• Limitation by Ascertainability (Reverse Engineering): An important exception exists: if the technical features of the invention embodied in a marketed product cannot be ascertained or understood by a person skilled in the art through ordinary analysis or reverse engineering techniques available at the time of the public working, then the sale or distribution of that product may not destroy novelty for those non-ascertainable features. For instance, in a case involving a pharmaceutical preparation with specific raw material particle sizes (Tokyo District Court, February 10, 2005, Hanrei Jihō No. 1906, p. 144, the "Branched-Chain Amino Acid-Containing Granular Pharmaceutical Preparation" case or 「分岐鎖アミノ酸含有医薬用顆粒製剤とその製造方法」事件), the court considered that if the particle size could not be determined from the marketed product using analytical techniques common at the filing date, novelty might be preserved for that specific feature. This underscores the importance of considering the state of analytical technology at the relevant time when assessing novelty based on prior product sales.

3. Inventions Described in a Distributed Publication or Made Available to the Public Through Telecommunication Lines (刊行物記載等 - kankōbutsu kisai tō) - Article 29(1)(iii)

This category covers disclosures in tangible written form or through electronic means.

• "Distributed Publication" (頒布された刊行物 - hampu sareta kankōbutsu):
  • This includes printed materials such as books, scientific journals, patent gazettes, conference proceedings, technical manuals, and even some types of theses or reports, provided they have been "distributed" – meaning made accessible to an unspecified public.
  • The mere existence of a document is not enough; it must have been disseminated or made available.
  • Landmark Supreme Court cases have provided guidance on what constitutes "distribution." The decision of July 4, 1980 (Minshu Vol. 34, No. 4, p. 570, the "Single-Lens Reflex Camera" case or「一眼レフカメラ」事件) found that West German patent application documents laid open for public inspection, where photocopies could be ordered and received by anyone within a reasonable timeframe (e.g., about two weeks), qualified as distributed publications.
  • Similarly, the Supreme Court decision of July 17, 1986 (Minshu Vol. 40, No. 5, p. 961, the "Measuring Box Rule" case or 「箱尺」事件) held that microfilm copies of Australian patent specifications made available for public viewing at multiple patent office locations constituted distributed publications. The focus is on public accessibility.
  • It's worth noting that amendments to the Patent Act in 1999 broadened Article 29(1)(i) (public knowledge) and (ii) (public working) to explicitly include foreign disclosures. This reduced the pressure to expansively interpret "distributed publication" to cover foreign disclosures that might not have been strictly "printed and distributed" in the traditional sense but were nonetheless publicly accessible abroad.
• "Made Available to the Public Through Telecommunication Lines": This part of the provision, also reflecting modernization, explicitly covers disclosures made via the internet, such as information on websites, online databases, and other electronic platforms, provided such information was accessible to the public before the critical date. The JPO provides guidelines on assessing the public availability of online information, considering factors like evidence of posting dates, accessibility controls, and the likelihood of access by the relevant public.

Exceptions to Loss of Novelty: Grace Period Provisions (Article 30)

Japanese patent law, under Article 30, provides a "grace period" (新規性喪失の例外規定 - shinkisei sōshitsu no reigai kitei). This allows an inventor or their successor to obtain a patent even if the invention was disclosed before the patent application was filed, provided certain conditions are met. The duration of this grace period was extended from 6 months to one year by amendments effective from June 9, 2018 (with some transitional provisions for disclosures made before that date).

There are two main scenarios covered:

1. Disclosure Against the Will of the Person Entitled to Obtain a Patent (Art. 30(1))

This applies if the novelty-destroying disclosure occurred against the will of the inventor or their rightful successor (e.g., through industrial espionage, unauthorized publication by a third party, or a breach of a confidentiality agreement by someone to whom the invention was disclosed in confidence).

• Negligence by Rights Holder: Even if the rights holder was somewhat negligent in safeguarding the information (e.g., insufficient instructions to employees about confidentiality), if the actual act of public disclosure was unauthorized and against their intent, this provision can still apply (see Tokyo High Court, April 26, 1972, Mutaishū Vol. 4, No. 1, p. 261).
• Filing Deadline: The patent application must be filed within one year from the date the invention first became publicly known against their will.
• Procedural Simplicity: A key feature of this provision is that the applicant does not need to claim the benefit of this grace period or submit specific proof at the time of filing the patent application. The issue can be raised and proven later if a novelty objection based on that involuntary disclosure arises during examination or in post-grant proceedings. This is because the rights holder may not even be aware of the involuntary disclosure when they file.

2. Disclosure Resulting from an Act of the Person Entitled to Obtain a Patent (Art. 30(2))

This is the more commonly invoked grace period provision and covers disclosures made by the inventor or their rightful successor themselves (or with their consent). This includes a wide range of activities:

• Publishing a paper in a scientific journal.
• Presenting the invention at a conference or exhibition.
• Selling or offering for sale products embodying the invention.
• Disclosing the invention on television, radio, or the internet.

The 2011 amendments significantly broadened the types of self-disclosures eligible for this grace period. Generally, most forms of public disclosure by the rights holder can now qualify, with a notable exception being disclosures made through the publication of the rights holder's own earlier patent applications in official patent gazettes (as other mechanisms like domestic or international priority claims are intended to handle the relationship between related patent filings by the same applicant).

• Filing Deadline: The patent application must be filed within one year from the date of the first such self-disclosure.
• Strict Procedural Requirements (Art. 30(3)): Unlike involuntary disclosures, invoking the grace period for self-disclosure requires strict adherence to procedural formalities:
  1. A statement claiming the benefit of the grace period under Article 30(2) must be submitted at the time of filing the patent application.
  2. Documentary evidence proving the facts of the disclosure (e.g., the date and content of the publication/presentation, and that it was made by or with the consent of the person entitled to the patent) must be submitted to the JPO Commissioner within 30 days from the patent application filing date.
     The JPO provides detailed guidance on these procedures and the types of proof required. For a series of related disclosures stemming from an initial disclosed inventive concept, submitting proof for the first relevant disclosure may sometimes suffice for subsequent, closely related disclosures under JPO practice.

Important Caveats Regarding Grace Period Provisions

While the grace period offers a crucial safety net, applicants must be aware of its limitations:

• Protection Limited to Specific Disclosures: The grace period only "cures" the novelty-destroying effect of the specific disclosure(s) for which the exception is properly claimed and proven. It does not provide general immunity against all prior art.
• No Protection Against Intervening Independent Third-Party Disclosures: If, after the applicant's own disclosure (for which they might claim a grace period) but before the applicant files their patent application, an independent third party makes a separate disclosure of the same invention, the grace period claimed by the applicant will not protect against this intervening third-party disclosure. The invention would then lack novelty due to the independent third-party act.
• No Retroactive Filing Date: The grace period does not change the effective filing date of the patent application. It merely excuses certain prior disclosures. Therefore, if an independent third party invents the same subject matter and files their own patent application before the grace period applicant files theirs (even if during the grace period applicant's one-year window), the grace period applicant's application may be rejected based on the first-to-file principle (Article 39) or due to an earlier-filed, later-published application by that third party (Article 29-2).

Conclusion

The assessment of novelty under Article 29(1) of the Japanese Patent Act is a rigorous process that requires a careful definition of the claimed invention and a thorough comparison against all forms of prior public disclosure available anywhere in the world before the application's effective filing date. While various types of acts can lead to a loss of novelty – including public knowledge, public working, and publication – Japanese law also provides a grace period under Article 30 that can, under strict conditions, excuse certain pre-filing disclosures. Navigating these rules effectively is essential for inventors and businesses seeking to secure valid patent protection in Japan, as novelty is a non-negotiable prerequisite for patentability.