Having a new idea is not enough to get a patent. The invention must also be non-obvious—not something a competent engineer in the field could have readily arrived at from publicly available knowledge. Together, novelty and inventive step (called “non-obviousness” in the United States) form the substantive core of patentability requirements in every major jurisdiction. This article explains what each requirement demands, how examiners evaluate them, and how they are contested in practice.
Novelty: The Requirement That the Invention Not Already Exist
An invention lacks novelty if, before the filing date, it was already disclosed to the public in any form anywhere in the world. Article 29(1) of Japan’s Patent Act identifies three categories of prior art that destroy novelty:
- Publicly known inventions (prior knowledge)
- Publicly worked inventions (prior use)
- Inventions described in publications or made available via the internet (prior publication)
“Publicly” means available to an indefinite number of people. Confidential disclosures under non-disclosure agreements do not constitute public knowledge. Academic conference presentations, journal publications, product sales, and website postings can each destroy novelty depending on timing and accessibility.
The novelty analysis is a question of identity: a single prior art document must disclose every element of the claimed invention (the “one-reference rule”). If any claimed element is absent from a single reference, novelty is not destroyed—though the invention may still be unpatentable for lack of inventive step, where combinations of references are permissible.
Grace Periods: Jurisdiction-Specific Rules
Most jurisdictions offer some form of “grace period”—a window during which the inventor’s own prior disclosure does not destroy novelty. Japan’s grace period under Article 30 of the Patent Act is 12 months. The US, following the America Invents Act (AIA, 2011), provides a 12-month grace period under 35 U.S.C. § 102(b)(1) for the inventor’s own disclosures.
However, the European Patent Office (EPO) does not provide a general grace period: any public disclosure before the filing date (including by the inventor) destroys novelty for European patent purposes, with only narrow exceptions for international exhibitions and clear abuse. For any invention intended for international protection, the safest strategy is filing before any public disclosure.
Inventive Step / Non-Obviousness: The Anti-Triviality Requirement
Article 29(2) of Japan’s Patent Act bars patents where “a person with ordinary skill in the art” (POSITA) could have “easily” arrived at the invention based on prior art. Unlike the novelty analysis, inventive step allows the examiner to combine multiple prior art references and consider common general knowledge in the field.
This requirement—inventive step in Japan and Europe, non-obviousness in the US—is the most frequently invoked reason for rejection and invalidation. According to JPO statistics, inventive step deficiencies account for approximately 60–70% of reasons for refusal in contested cases.
Japan’s Examination Guidelines
The JPO’s Examination Guidelines for Patents and Utility Models (revised 2022) prescribe the following analytical sequence for inventive step:
- Select the closest prior art (primary reference)
- Identify the differences between the claimed invention and the primary reference
- Determine whether the differences are suggested by secondary references or common general knowledge
- Assess whether the skilled person would have had motivation to combine the primary and secondary references
- Consider whether unexpected advantageous effects support inventive step
Motivation to combine can be inferred from technical proximity, shared problem, common function, or an explicit suggestion in one of the references. Conversely, an “obstacle to combination”—for instance, if combining the references would undermine the primary reference’s purpose—can negate motivation and support inventive step.
The “Person of Ordinary Skill in the Art”
The POSITA is a legal fiction: a hypothetical technician who has absorbed all prior art in the field but possesses no creative spark. This person is neither a genius nor a novice. In interdisciplinary fields (for example, the intersection of molecular biology and computer science in bioinformatics), the POSITA may be conceptualized as a team of specialists rather than a single individual.
The definition of the POSITA is often contested in proceedings because it directly affects whether a claimed difference over the prior art would be considered obvious. A more narrowly defined POSITA with limited background knowledge is less likely to find a combination obvious; a broadly defined one may find it routine.
US Non-Obviousness Under 35 U.S.C. § 103
The US non-obviousness standard was shaped by the Supreme Court’s decision in Graham v. John Deere Co. (383 U.S. 1, 1966), which established the “Graham factors”:
- The scope and content of the prior art
- The differences between the claimed invention and the prior art
- The level of ordinary skill in the pertinent art
- Secondary considerations (objective evidence of non-obviousness)
Secondary considerations—also known as objective indicia of non-obviousness—include commercial success of the invention, long-felt but unresolved need, failure of others to solve the same problem, and unexpected results. These factors can save a claim from an obviousness rejection even when the technical differences appear marginal.
KSR International Co. v. Teleflex Inc. (550 U.S. 398, 2007) significantly liberalized the non-obviousness test by rejecting the rigid “teaching, suggestion, or motivation” (TSM) test that had required examiners and courts to identify an explicit reason for combining references. After KSR, obvious combinations based on common sense, known solutions to known problems, and predictable variations are more readily found obvious—making the US standard somewhat broader in practice than pre-2007 doctrine.
European Problem-Solution Approach
The EPO applies the “problem-solution approach” as its standard method for assessing inventive step (EPC Article 56; Guidelines for Examination, Part G, Chapter VII). The method proceeds as follows:
- Determine the closest prior art
- Identify the objective technical problem actually solved by the distinguishing features of the invention
- Assess whether the skilled person, seeking to solve that objective technical problem, would have arrived at the claimed solution with a reasonable expectation of success
A distinctive feature of the EPO approach is the “objective reformulation” of the technical problem: if the problem stated in the application turns out to be incorrect or too ambitious given the prior art, the EPO reformulates it objectively. This prevents applicants from artificially inflating the technical problem to make the solution appear less obvious. The requirement for a “technical effect” underpinning the problem-solution analysis also shapes how software and business method inventions are assessed in Europe.
How Novelty and Inventive Step Are Contested in Practice
In examination, an Office Action citing lack of inventive step invites the applicant to respond with written arguments and/or claim amendments. The written argument typically challenges the examiner’s proposed motivation to combine references, argues for the presence of an obstacle to combination, and highlights unexpected advantageous effects. Claim amendments narrow the scope to incorporate additional limitations that distinguish the invention from the cited art.
After grant, patents may be attacked for lack of novelty or inventive step through post-grant procedures: inter partes review (IPR) before the US Patent Trial and Appeal Board (PTAB), opposition proceedings before the EPO’s Opposition Division, or patent invalidation trials before Japan’s JPO. In Japan, the Supreme Court’s Kilby decision (April 11, 2000) held that defendants in infringement suits may raise patent invalidity as a defense—a ruling that effectively merged infringement and invalidity proceedings into a single battlefield.
The next article examines the complete patent prosecution process, from filing through grant, with attention to timelines, costs, and the strategic choices available at each stage.
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