What Qualifies as a Patentable "Invention" Under Article 2(1) of the Japanese Patent Act?

The gateway to patent protection in Japan, as in most jurisdictions, is the fundamental requirement that the subject matter sought to be protected must first qualify as an "invention" (発明 - hatsumei). Article 2(1) of the Japanese Patent Act provides the core definition: an invention is "the highly advanced creation of technical ideas utilizing the laws of nature." This definition, seemingly concise, encapsulates several distinct elements that collectively serve to delineate the boundaries of patentable subject matter, even before considerations of novelty, inventive step, or industrial applicability arise.

Furthermore, Article 29(1) of the Patent Act, which sets out the basic requirements for patentability, begins by stating that "An inventor of an invention that is industrially applicable may be entitled to obtain a patent for the said invention..." This introduces the additional prerequisite of industrial applicability. Understanding these foundational definitions is crucial for anyone seeking to navigate the Japanese patent system.

Dissecting the Definition of "Invention" (Article 2(1))

Each component of the Article 2(1) definition – "highly advanced," "creation," "technical ideas," and "utilizing the laws of nature" – has been interpreted and refined by the Japan Patent Office (JPO) and the courts.

1. "Creation of Technical Ideas" (技術的思想の創作 - gijutsuteki shisō no sōsaku)

This phrase embodies two key aspects: the subject matter must be a "technical idea" and it must be a "creation."

a. Technical Idea (技術的思想 - gijutsuteki shisō)

A "technical idea" implies something that is concrete, objective, and capable of being put into practice to achieve a reproducible result. This distinguishes patentable inventions from:

• Abstract concepts or mental steps: Purely abstract ideas, mathematical algorithms not tied to a specific technical application, or methods of mental reasoning are not considered technical ideas.
• Artistic creations or aesthetic designs: These are typically protectable by copyright or design rights, not patents, as they lack the requisite technical character directed at solving a technical problem.
• Incomplete or Inoperable Ideas: The idea must be sufficiently developed to be workable. It needs to be "completed" (完成 - kansei) to the extent that it can be implemented.
  • The Supreme Court decision of January 28, 1969 (Minshu Vol. 23, No. 1, p. 54), often referred to as the "Nuclear Reactor" case (「原子炉」事件), found that an invention related to controlling nuclear fission was not a completed invention because it was deemed unsafe and difficult to control consistently, meaning it lacked reliable and repeatable implementation. It is important to note that safety per se is not a universal requirement for an invention to be patentable; rather, in this specific high-stakes context, the inability to safely and controllably operate the reactor meant the technical idea itself was not practically realizable in a repeatable manner.
  • Conversely, the Supreme Court decision of February 29, 2000 (Minshu Vol. 54, No. 2, p. 709), the "New Peach Variety Breeding Method" case (「桃の新品種黄桃の育種増殖法」事件), addressed the repeatability (反復可能性 - hampuku kanōsei) of a plant breeding method. The Court held that even if the probability of successfully breeding a new plant variety through a specific hybridization process is low, if the method makes such breeding possible and the resulting new variety can then be consistently reproduced through established propagation techniques, the requirement for repeatability (as part of being a workable technical idea) is satisfied.

b. Creation (創作 - sōsaku)

The term "creation" signifies that the invention must be man-made and not merely a discovery of something that already exists in nature.

• Discoveries vs. Creations: A mere discovery of a law of nature, a natural phenomenon, or a substance as it exists in its natural state is not a patentable creation. For example, identifying a new mineral or a previously unknown scientific principle is a discovery, not an invention.
• Human Intervention: However, if human ingenuity is applied to a natural discovery to yield a new technical utility or a new form not found in nature, it can qualify as a creation.
  • Newly Synthesized Chemical Compounds: A newly synthesized chemical compound is patentable if a specific utility (usefulness) for it is also identified. Once this is established, the patent typically covers the compound itself, and its protection is not limited to the first identified use but can extend to other subsequently discovered uses. This broad protection is justified on the grounds of incentivizing the difficult work of synthesizing new compounds and preventing others from free-riding on this by simply finding additional uses for the already disclosed compound.
  • Known Chemical Compounds with Newly Discovered Uses (Use Inventions - 用途発明 - yōto hatsumei): If a new and non-obvious technical use is discovered for a known chemical compound, this can be patented as a "use invention". While theoretically such inventions are methods of use, Japanese practice has long allowed them to be claimed as product claims limited by that specific use (e.g., "Compound X for use in the treatment of disease Y," or "Composition comprising Compound X for use as an insecticide"). The protection granted is generally limited to the newly discovered use.
  • Naturally Occurring Substances: The mere discovery of a substance existing in nature is not a creation. However, if such a substance is isolated from its natural environment for the first time, purified to a state not found in nature, and a specific utility is identified for it, this can constitute a patentable invention. The human intervention involved in isolating, purifying, and identifying a utility elevates it beyond a mere discovery.

2. "Utilizing the Laws of Nature" (自然法則を利用した - shizen hōsoku o riyō shita)

This is a fundamental gatekeeper, requiring that the technical idea be grounded in the principles that govern the physical, chemical, or biological world. It serves to exclude subject matter that operates outside these natural laws.

Categories Typically Excluded as Not Utilizing Laws of Nature:

• Laws of nature themselves: Scientific principles or mathematical formulae as such (e.g., Newton's laws of motion, E=mc²) are not patentable.
• Purely mental processes: Methods of calculation, linguistic schemes, methods of teaching, or strategies for playing games that rely solely on human thought or decision-making are excluded. The Supreme Court decision of April 30, 1953 (Minshu Vol. 7, No. 4, p. 461), the "Single Telegraphic Code Word Creation Method" case (「欧文字単一電報隠語作成方法」事件), found a method for creating telegraphic codes using combinations of letters, numbers, and symbols, without any apparatus or use of natural forces, to be unpatentable.
• Arbitrary arrangements or man-made rules: Economic theories, business methods per se (i.e., purely commercial or financial schemes lacking a technical implementation utilizing natural laws), accounting methods, or advertising schemes are generally not considered to utilize laws of nature. For instance, a system for organizing accounting data based on economic principles was found unpatentable (Tokyo District Court, January 20, 2003, Hanrei Jihō No. 1809, p. 3, the "Fund-Specific Balance Sheet" case or「資金別貸借対照表」事件). Similarly, a method for rotating advertisements on utility poles based on a schedule, without employing any natural force for the rotation, was deemed not an invention (Tokyo High Court, December 25, 1956, Gyōshū Vol. 7, No. 12, p. 3157, the "Utility Pole Advertising Method" case or 「電柱広告方法」事件).

Inventions Incorporating Human Mental Activity:

Many inventions involve some degree of human interaction or mental input. The mere presence of a human mental step does not automatically disqualify an invention. The assessment is made on the invention as a whole.

• If the core of the invention or the primary means for solving the technical problem relies on the utilization of natural laws, even if some steps involve human judgment or interpretation, the invention may be patentable.
• Conversely, if the technical idea is directed primarily at the human mental activity itself, or if the human activity is the dominant problem-solving element, it is unlikely to be considered an invention utilizing natural laws.
  • The IP High Court decision of August 26, 2008 (Hanrei Jihō No. 2041, p. 124), the "Phoneme Index Matrix Bilingual Dictionary" case (「音素索引多要素行列構造の英語と他言語の対訳辞書」事件), found an invention utilizing the linguistic characteristic that non-native English speakers find consonants easier to recognize than vowels, implemented in a dictionary structure, to be patentable because it used a natural human cognitive characteristic to achieve a repeatable effect in information retrieval.
  • However, in the IP High Court decision of February 24, 2016 (Hanrei Times No. 1437, p. 130), the "Energy Saving Action Sheet" case (「省エネ行動シート」事件), an invention involving a sheet that displayed potential energy savings from various actions was found unpatentable because its technical significance was deemed to be directed solely at influencing human mental activity (i.e., aiding a user's understanding and decision-making regarding energy conservation) rather than providing a technical means that itself utilized natural laws to achieve a technical effect.

Software-Related Inventions:

The 2002 amendments to the Patent Act explicitly included "programs, etc." (プログラム等 - puroguramu tō, defined in Art. 2(4) to include computer programs and data structured for computer processing) within the definition of "product" inventions (Art. 2(3)(i)). However, to be patentable, software-related inventions must still satisfy the Art. 2(1) definition of "invention," meaning they must utilize laws of nature and embody a technical idea.

• JPO Examination Guidelines: Typically, software is considered to utilize laws of nature if it achieves specific control over hardware (e.g., controlling a machine) or performs information processing based on the physical, chemical, or biological properties of an object.
• If this is not clear, the guidelines assess whether the invention achieves specific information processing (beyond routine data handling) through the cooperative functioning of software and hardware resources.
• Not Merely Computerizing Abstract Ideas: Simply automating a known manual process, a business rule, or an abstract idea using a general-purpose computer does not automatically render it a patentable invention. The invention must possess a technical character that goes beyond the generic functions of a computer. The IP High Court decision of September 24, 2014 (2014 (Gyō-ke) 10014), the "Knowledge Base System" case (「知識ベースシステム」事件), denied patentability to a system that used a computer for general data recording and display of abstract concepts and man-made rules, finding it did not utilize laws of nature.

Business Method Inventions:

A pure business method (e.g., a new sales strategy or financial scheme) is not patentable as it is typically considered an artificial arrangement or economic principle. However, a business method implemented using specific technical means that themselves utilize laws of nature can be patentable.

• Computer Implementation: Most patentable business methods involve implementation via computer systems and software, where the technical features of the implementation (e.g., specific data processing steps, network communications achieving a technical effect) provide the necessary utilization of natural laws. (See, e.g., IP High Court, May 25, 2009, Hanrei Jihō No. 2105, p. 105, the "Accounting System for Travel Agencies" case or 「旅行業向け会計処理装置」事件).
• Physical Apparatus: Business methods can also be patentable if they are carried out using novel physical machinery or tools that contribute to solving a technical problem within the business context (e.g., IP High Court, October 17, 2018, 2017 (Gyō-ke) 10232, the "Steak Provision System" case or 「ステーキの提供システム」事件, involving a specific physical system for serving food).

AI-Related Inventions:

Artificial intelligence (AI)-related inventions are generally assessed similarly to other software-related inventions.

• A trained AI model, claimed for example as a program or as part of a system including hardware, can be patentable if its operation involves specific information processing that utilizes laws of nature to achieve a technical effect. For example, the JPO Examination Handbook includes an example of a "trained model for analyzing accommodation reputation," which is deemed patentable subject matter because it is embodied as a program with a specific neural network structure and performs concrete software processing. The claim would typically need to define aspects of the AI model's structure or the specific data processing it performs in conjunction with hardware.

3. "Highly Advanced" (高度のもの - kōdo no mono)

This element of the definition primarily serves to distinguish patentable "inventions" from "devices" (考案 - kōan) which are eligible for protection under the Utility Model Act. The Utility Model Act defines a device as "the creation of technical ideas utilizing the laws of nature" but omits the "highly advanced" requirement (Utility Model Act, Art. 2(1)).

In practice, the "highly advanced" criterion rarely acts as an independent hurdle for patentability distinct from the requirement for an inventive step (非容易推考性 - hi-yōi suikō-sei) under Patent Act Article 29(2). If an invention possesses an inventive step (i.e., it would not have been easily conceived by a person skilled in the art), it is generally considered to be sufficiently "highly advanced" to qualify as a patentable invention. The substantive examination of the level of technical achievement is primarily conducted under the inventive step analysis.

Other Fundamental Requirements: Industrial Applicability and Non-Prohibited Inventions

Even if a concept meets the Article 2(1) definition of an "invention," two further overarching requirements must be satisfied:

1. Industrial Applicability (産業上の利用可能性 - sangyōjō no riyōkanōsei) (Article 29(1) preamble)

The invention must be "industrially applicable." "Industry" is interpreted broadly to include manufacturing, agriculture, mining, commerce, services, and so on. This requirement excludes inventions that:

• Cannot be used in any practical industry.
• Are clearly impossible to use in practice (e.g., a perpetual motion machine).
  The threshold for industrial applicability is generally low. The invention does not need to have proven commercial value or market success; some potential for industrial use is sufficient. Technical disadvantages alone do not negate industrial applicability (Tokyo High Court, December 25, 1986, Mutaishū Vol. 18, No. 3, p. 579, the "Banknote" case or「紙幣」事件).

The Medical Methods Exception: A significant category of subject matter deemed to lack industrial applicability in Japan (and many other countries) consists of methods for the medical surgery, therapy, or diagnosis of human beings practiced on the human body.

• Rationale: This exclusion is rooted in ethical considerations, the principle that human life and health should take precedence over proprietary rights, and the practical concern that medical professionals should not be hindered by patent infringement fears when providing urgent care (Tokyo High Court, April 11, 2002, Hanrei Jihō No. 1828, p. 99).
• Patentability of Medical Products: In contrast, medical products themselves (e.g., pharmaceuticals, medical devices, diagnostic agents used in vitro) are considered industrially applicable and are patentable subject matter. The manufacture and sale of such products are clearly industrial activities.
• Use of Patented Medical Products by Doctors: While medical products are patentable, the act of a doctor using a patented drug or device in the direct treatment or diagnosis of a patient is generally not considered an act "in the course of trade" by the doctor for the purposes of infringement, or is otherwise considered exempt from patent enforcement to ensure that patient care is not impeded. Furthermore, Article 69(3) of the Patent Act provides a specific exemption for medicines (and processes for preparing them) that are compounded according to a doctor's or dentist's prescription, and for the medicines so compounded.

2. Non-Prohibited Inventions (Article 32)

Article 32 of the Patent Act states that "inventions liable to injure public order, morality or public health shall not be patented." This is a rarely invoked ground for refusal or invalidation.

• The standard is high; an invention must pose a genuine threat to fundamental societal values.
• Simply being subject to other legal or regulatory restrictions does not automatically mean an invention contravenes public order or morality, as such regulations can change over time (as noted in the "Banknote" case regarding currency reproduction).

Conclusion

The definition of a patentable "invention" under Article 2(1) of the Japanese Patent Act, combined with the requirement for industrial applicability, serves as a critical filter for determining what types of innovations can receive patent protection. It requires a "highly advanced creation of technical ideas utilizing the laws of nature." This multi-faceted definition excludes mere discoveries, abstract ideas, purely mental processes, and business methods lacking a concrete technical implementation, while accommodating innovations across a wide range of technological fields, including the evolving areas of software, AI, and biotechnology. The specific exclusion of medical methods performed on the human body reflects important ethical and public health considerations. A thorough understanding of these foundational principles is the essential first step in any assessment of patentability in Japan.