--- title: "Prior Art and How to Search for It | Pitch" description: "What counts as prior art under the European Patent Convention, what a patentability search covers, how it is done and what it cannot tell you." url: https://www.pitch.law/academy/prior-art-search-patents --- [pitch](https://www.pitch.law/) [Academy](https://www.pitch.law/academy) [Patents](https://www.pitch.law/academy/topics/patents) # Prior Art and How to Search for It What counts as prior art under the European Patent Convention, what a patentability search covers, how it is done and what it cannot tell you. - By By Bart Lieben, Attorney-at-Law - Published 26 October 2026 ## The legal framework A patent can only be granted for an invention that is new and involves an inventive step (Arts. 52, 54 and 56 EPC). Both tests are measured against the prior art, called the state of the art in the EPC. ### What counts The state of the art comprises everything made available to the public anywhere in the world, in any language, by written or oral description, by use, or in any other way, before the filing date or, if a priority is validly claimed, the priority date (Art. 54(2) EPC). Nothing is excluded because it is obscure, old or foreign. A journal article, a conference talk, a product on a shelf in another continent, a thesis in a university library and an earlier patent document all count. Your own disclosure counts too. The EPC has no general grace period. Only an evident abuse against you and display at certain officially recognised exhibitions are excluded (Art. 55 EPC). A presentation to potential customers, a post, a trade-fair demonstration or a sale before filing can therefore destroy novelty. Earlier European patent applications that were filed before your date but published afterwards also count, but only for novelty and not for inventive step (Art. 54(3) EPC). This matters when a competitor files shortly before you. ### Novelty and inventive step An invention is new if it is not disclosed in a single prior art document in all its features. It involves an inventive step if, having regard to the prior art, it is not obvious to a person skilled in the art (Art. 56 EPC). The EPO usually assesses this through the problem-and-solution approach: it identifies the closest prior art, determines the technical problem the invention solves compared with it, and asks whether the solution would have been obvious. ### Timeline A European patent application is published 18 months after the filing or priority date (Art. 93 EPC). Until then it is not visible, so any search is blind to recent filings. A priority period of 12 months applies to patents (Art. 87 EPC). ## In practice A search is built in stages. First the invention is described in terms of technical features, not marketing language. Next, search strategies are developed along several lines: classification codes (the Cooperative Patent Classification), keywords and synonyms in more than one language, and citation chains forward and backward from key documents. Patent databases such as the EPO's Espacenet are the starting point, and non-patent literature such as articles, standards, theses and product manuals is added because it often decides the outcome. The result is a set of documents that is read and ranked by closeness. An attorney then assesses what remains available as a claim and how broad it can be. [Our patent analysis and research function](https://www.pitch.law/technologies/patent-intelligence) structures the retrieval and the comparison of claim features with the documents found, and the attorney does the reading and the legal assessment. Consider a Ghent company that has developed a sensor for monitoring greenhouse humidity. Before filing, a search finds a Japanese patent application that discloses a similar sensor with a different housing, and a university paper that describes the signal processing. Neither disclosed the combination. The company files with claims centred on the combination, avoiding a broader claim that would have been refused. Had the search been skipped, the broad claim would probably have been narrowed after the EPO's own search, at a later and more expensive stage. A different company showed a prototype at a trade fair in March and asked about filing in June. That demonstration is itself prior art against the application. A search cannot repair this, which is why the first question in every file is what has already been shown. For competitors' filings and for staying current after the first search, a [patent watch](https://www.pitch.law/technologies/patent-watch) repeats the search on a schedule and reports what is new. ## Frequently asked questions ### Is a prior art search legally required before filing? No. But the EPO carries out its own search after filing, and its result may force narrower claims. Searching beforehand lets you draft with the closest documents in view and decide whether to file at all. ### Does a search guarantee that no relevant document exists? No. Unpublished applications, documents in languages or databases not covered, and oral or public use that was never recorded cannot be found. A search reduces risk but does not eliminate it. ### Does a patentability search tell me whether I can sell my product? No. That is a different question, answered by a [freedom-to-operate analysis](https://www.pitch.law/academy/freedom-to-operate-analysis). Patentability concerns whether you can obtain a patent; freedom to operate concerns whether others' patents block you. ### Can I rely on my own earlier publication being forgiven? Generally not. The EPC grace period is extremely narrow. Other jurisdictions have more generous rules, but protection in Europe may be lost. ## How this connects Patentability searches and freedom-to-operate analyses are the core of [patent research](https://www.pitch.law/solutions/patent-research). The functions that support them are described in [patent analysis and research](https://www.pitch.law/technologies/patent-intelligence) and [patent watch](https://www.pitch.law/technologies/patent-watch). ## In short - What prior art is, and what it is not - Why your own earlier disclosure counts - How a professional search is built - Limits of any search of published documents ## Related solutions - [Solutions](https://www.pitch.law/solutions/patent-research) ### [Patent Research](https://www.pitch.law/solutions/patent-research) [Prior art, patentability and freedom-to-operate answers from attorneys, built on structured patent data and checked citations.](https://www.pitch.law/solutions/patent-research) ## Technology we use - [Technology](https://www.pitch.law/technologies/patent-intelligence) ### [Patent Analysis and Research](https://www.pitch.law/technologies/patent-intelligence) [Analysis of third-party patents and research answers built on European Patent Office data and UPC and EPO case law, with every citation checked and every opinion signed by an attorney.](https://www.pitch.law/technologies/patent-intelligence) - [Technology](https://www.pitch.law/technologies/patent-watch) ### [Patent Watch](https://www.pitch.law/technologies/patent-watch) [Scheduled watches on European Patent Office data that report what other parties publish, grant or change in your field, with every hit read by an attorney.](https://www.pitch.law/technologies/patent-watch) ## More in Patents - ### [Freedom-to-Operate Analysis](https://www.pitch.law/academy/freedom-to-operate-analysis) [What a freedom-to-operate analysis is, how claims are read against a product, what it can and cannot tell you, and what to do when it finds a problem.](https://www.pitch.law/academy/freedom-to-operate-analysis) - ### [The Unified Patent Court](https://www.pitch.law/academy/unified-patent-court) [How the Unified Patent Court is organised, what it decides, how its proceedings differ from national courts, and what the opt-out means for your European patents.](https://www.pitch.law/academy/unified-patent-court) - ### [The Unitary Patent](https://www.pitch.law/academy/unitary-patent) [What unitary effect is, which states it covers in October 2026, how it differs from validating a European patent country by country, and when each route makes sense.](https://www.pitch.law/academy/unitary-patent) ## Let’s talk Tell us what you’re working on. 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