Is My Invention Patentable in Japan? Understanding the Core Requirements

Japanese Attorney at Law - Bengoshi L.L.

• 7 min read

Before diving into the more commonly discussed patentability criteria like novelty and inventive step, an initial and crucial hurdle must be cleared for any invention seeking protection under Japanese patent law: it must first qualify as a statutory "invention." This foundational assessment determines whether an idea or creation is even eligible for patent consideration. Understanding these core requirements is essential for anyone, especially businesses, looking to protect their technological innovations in Japan.

So, what constitutes an "invention" in the eyes of the Japanese Patent Act?

The Statutory Definition of an "Invention" in Japan

Article 2, Paragraph 1 of the Japanese Patent Act defines an "invention" as "a highly advanced creation of a technical idea utilizing a law of nature." This definition, though seemingly concise, breaks down into four key requirements that must all be met:

  1. Utilization of a Law of Nature (自然法則の利用 - Shizen Hōsoku no Riyō)
  2. Being a Technical Idea (技術的思想 - Gijutsu-teki Shisō)
  3. Creativity (創作 - Sōsaku)
  4. Advanced Nature (高度性 - Kōdosei)

These requirements function as a gateway; if any one of them is not satisfied, the subject matter is not considered a statutory "invention," and thus cannot proceed to the subsequent stages of examination for patentability (such as novelty, inventive step, and industrial applicability). Let's explore each of these in detail.

Requirement 1: Utilization of a Law of Nature (自然法則の利用)

This requirement mandates that an invention must harness or apply principles, forces, or causal relationships found in the natural world. It's about leveraging the inherent workings of nature to achieve a specific technical outcome.

What is generally excluded under this requirement?

  • Laws of Nature Themselves: Fundamental scientific principles or mathematical formulas, such as Newton's laws of motion or Einstein's E=mc², are not patentable in themselves. These are considered discoveries that belong to all humankind.
  • Discoveries of Natural Phenomena without Technical Application: Simply finding something that already exists in nature, like a new mineral or a previously unknown scientific principle, without applying it to a specific technical purpose, is a discovery, not an invention.
  • Things Contrary to Laws of Nature: Concepts that defy established scientific principles, such as perpetual motion machines, are not considered to utilize laws of nature and are therefore unpatentable. The Infinite Power Generation Method Case (Tokyo High Court, June 29, 1973) is an example where an alleged invention claiming such a device was denied.
  • Purely Mental Processes or Human-Made Rules: Arbitrary arrangements, rules for games, business methods purely reliant on human skill or economic principles without a technical aspect, linguistic rules, or mathematical algorithms per se fall outside this scope. For instance, a new accounting method or a strategic game rule, if devoid of a concrete technical implementation leveraging natural laws, would not qualify. The Loan Balance Sheet Case (Tokyo District Court, January 20, 2003, a utility model case) found that a particular method of creating balance sheets, being an artificial arrangement, lacked the utilization of a law of nature.
  • Economic Laws: Principles governing economic behavior or market predictions are not considered laws of nature for patent purposes.
  • Subject Matter Lacking Repeatability/Reproducibility: An invention must be capable of being worked repeatedly by a person skilled in the art to achieve the same result under given conditions. If an outcome is a one-off, chance event that cannot be reliably reproduced, it suggests a lack of consistent utilization of natural laws. However, the bar for repeatability isn't always absolute perfection. The Yellow Peach Breeding and Propagation Method Case (Supreme Court, February 29, 2000) suggested that even if the success rate is low, as long as there is a possibility of reproduction which can lead to industrial development through improvement, it can still be considered an invention.

What is included?

The focus is on the application of a law of nature to achieve a concrete, technical purpose. For example, while the law of gravity itself is not patentable, a machine that utilizes gravity to perform a specific function could be.

Modern Interpretations for New Technologies:

In fields like software and biotechnology, the application of this requirement has evolved.

  • Software-related inventions: Initially, there were debates about whether software, being essentially a set of instructions or algorithms, utilized laws of nature. However, current Japanese practice, as reflected in the JPO's Examination Guidelines, generally accepts software-related inventions if the information processing by the software is concretely realized using physical hardware resources (e.g., CPU, memory) to achieve a technical effect. This linkage to the physical world through hardware operation allows it to be seen as utilizing natural laws (e.g., laws of electricity governing hardware). The text notes that this requirement tends to be interpreted more leniently for such inventions now.
  • Biotechnology inventions: Discovering a gene in its natural state is not an invention. However, isolating a gene, elucidating its function, and then using it for a specific technical purpose (e.g., to produce a therapeutic protein or in a diagnostic method) can be considered to utilize laws of nature and be patentable, assuming other criteria are met.

Requirement 2: Being a Technical Idea (技術的思想)

This requirement stipulates that an invention must be a "technical idea"—a concrete and objective means conceived to achieve a certain practical purpose in a technical field.

Key Aspects:

  • Purposefulness (Utility - 有用性): The idea must be aimed at achieving a specific, practical objective. An idea without any discernible purpose or utility is not considered a technical idea. This is particularly relevant in chemical inventions, where the utility of a new compound might need to be demonstrated. The Herbicidal Imidazole Derivatives Case (Tokyo High Court, March 22, 1994) dealt with the utility of chemical compounds.
  • Concreteness and Objectivity: The idea must be specific and capable of being objectively understood and implemented by others skilled in the relevant technical field. Abstract philosophical concepts, economic theories as such, or personal skills, "knacks," or artisanal techniques that cannot be systematically taught or reproduced by others are not technical ideas. The invention must be sufficiently concrete to be communicable and workable.
  • Completeness (Workability): The technical idea must be developed to a stage where it is, in principle, ready to be put into practice by a person skilled in the art to achieve its intended purpose. A mere wish or an incomplete, half-baked concept that lacks the necessary details for implementation is not a "completed" technical idea. The Nuclear Energy Generation Device Case (Supreme Court, January 28, 1969) touched upon the necessity for an invention to be "completed."
  • Distinction from Mere Expression (Idea/Expression Dichotomy): Patent law protects the technical idea itself (the "content" or "what is to be conveyed"), not the specific way it is expressed or presented. The latter falls within the domain of copyright. For example, the underlying algorithm or technical functionality of a computer program can be a patentable technical idea, while the specific source code written to implement that algorithm is a form of expression protectable by copyright.

A "technical idea" is therefore a practical, replicable solution to a problem in a technical field.

Requirement 3: Creativity (創作)

The term "creation" (創作 - sōsaku) implies that the invention must be something artificially made or devised by human ingenuity. It should not be a mere discovery of something that already exists in nature, waiting to be found.

Discoveries vs. Creative Inventions:

  • Discoveries: Simply finding and recognizing natural substances (e.g., a new mineral or plant species in its natural state), natural phenomena (e.g., a new law of physics), or properties of existing things, without any human intervention to modify or apply them in a novel technical way, constitutes a discovery, not a patentable creation. Discoveries are valuable contributions to human knowledge but are generally considered part of the common heritage, not subject to exclusive patent rights that could unduly restrict their broad application.
  • Creative Inventions:
    • Artificial Products: Newly synthesized chemical compounds, genetically engineered microorganisms, or artificially bred plant varieties resulting from human technical intervention are considered creations.
    • Isolated Natural Substances with Identified Utility: While a substance as it exists in nature is a discovery, the act of isolating that substance from its natural environment, purifying it, and identifying a specific, new, and non-obvious technical utility for it can qualify as a creative invention. For example, isolating a previously unknown microorganism and discovering its antibiotic properties for a specific medical use.
    • Use Inventions (用途発明 - Yoto Hatsumei): Finding a new and non-obvious technical use for a known substance or article can also be considered a "creation." For instance, discovering that a known chemical compound, previously used as a dye, has an unexpected and useful application as a pharmaceutical. The Koi Carp Breeding Method Case (Tokyo High Court, February 13, 1990) held that while the color-enhancing effect of Spirulina platensis on red Koi carp was a discovery, the method of feeding it to the carp to enhance their red color was a patentable invention.

The line between discovery and creation can be subtle, particularly in fields like chemistry and biotechnology. The key often lies in the degree of human technical intervention and the identification of a specific, concrete technical application.

Requirement 4: Advanced Nature (高度性)

The final requirement is that the invention must be of a "highly advanced" (高度 - kōdo) nature.

Purpose and Relationship with Other Concepts:

  • Distinction from Utility Models: This requirement was historically introduced primarily to distinguish patentable inventions from "devices" (考案 - kōan), which are protected under Japan's Utility Model Law. Utility models are generally for creations of a lesser inventive degree, sometimes called "petty patents," and are subject to a less stringent (or no) substantive examination process and have a shorter term of protection. The Patent Act's "advanced nature" criterion aims to reserve patent protection for more significant technological contributions.
  • Overlap with Inventive Step: In practice, the "advanced nature" requirement is often seen as largely overlapping with, or being subsumed by, the separate patentability requirement of "inventive step" (進歩性 - shinposei, akin to non-obviousness). Inventive step requires that the invention would not have been easily conceived by a person skilled in the relevant art based on the prior art. If an invention possesses inventive step, it is generally considered to meet the "advanced nature" threshold. The provided text notes that in actual JPO examination practice, the "advanced nature" requirement often loses its independent significance and is effectively assessed as part of the inventive step analysis.

While theoretically distinct (advanced nature being an absolute assessment of the invention's technical level, and inventive step being a relative assessment against prior art), the practical impact of "advanced nature" as an independent filter is limited when inventive step is also rigorously applied.

Interplay and Practical Application of the Requirements

While these four requirements are listed separately, there can be conceptual overlaps, particularly between the utilization of a law of nature, being a technical idea, and creativity. The critical point for businesses and inventors is that the subject matter must clear all these hurdles to be considered a statutory "invention" before it can even be assessed for further patentability criteria such as novelty, inventive step, and industrial applicability. Failure to meet any one of these foundational requirements will lead to the rejection of a patent application on the grounds that it does not pertain to an "invention" under the Act.

Conclusion

Determining whether an idea qualifies as a patentable "invention" under Japanese law involves a careful assessment against these four core requirements: the utilization of a law of nature, the presence of a technical idea, an element of human creativity beyond mere discovery, and a certain advanced nature. For businesses seeking to protect their innovations in Japan, a thorough understanding of these criteria is the essential first step. It helps in identifying patentable subject matter early, in drafting applications that clearly articulate these elements, and in navigating the initial stages of the patent examination process, ultimately strengthening the foundation for securing robust patent protection.