[Taiwan] How Hindsight Bias Quietly Creeps into Patent Litigation (Part 1)
[ September 01, 2026 ] >Back| Insights from the Supreme Court 2024 Tai-Shang-Zi No. 453 Civil Judgment (Part 1 of 2) Article 22, Paragraph 2 of the Patent Act provides that an invention shall not be patented if a person having ordinary skill in the art to which the invention pertains could have easily made the invention based on prior art existing before the filing date. This constitutes a defense of patent invalidity based on lack of inventive step. In other words, if an ordinary practitioner in the relevant field could have easily arrived at the invention claimed in the patent at issue by simply combining the teachings of Citation A (prior art) and Citation B, the patent at issue lacks inventive step and does not merit the grant of patent rights and patent protection. However, the concepts of a "person having ordinary skill in the art" and "could have easily made" remain indeterminate legal concepts that, even today, are difficult to define with precision. A person who has ordinary skill in the art refers to a hypothetical person who possesses ordinary knowledge in the technical field to which the invention pertains, as well as the ordinary ability to perform routine work and experiments (see Supreme Administrative Court 2016 Pan-Zi No. 503 Administrative Judgment). As to whether an invention "could have been easily made," the Patent Examination Guidelines determine whether there was a motivation to combine the cited references by considering the relevance of the technical fields, the commonality of the problems to be solved, the commonality of functions or effects, and the existence of any teachings or suggestions (hereinafter, the "factors indicating a lack of inventive step"). Where none of the four factors supporting inventive step, namely teaching away, overcoming technical prejudice, advantageous or unexpected effects, and solving a long-standing problem, is present (hereinafter, the "factors supporting inventive step"), the invention is considered to have been easily made. In court practice, the focus of the parties' arguments generally falls on whether the citations disclose the technical features of the patent at issue, while the reasoning as to whether a person having ordinary skill in the art could have easily made the invention "naturally emerges" in the process. Put simply, the issue is omitted. The view supporting such omission holds that the reasoning on whether a person having ordinary skill in the art could have easily made the invention is already encompassed within the overall analysis of inventive step and therefore need not be discussed separately. The Intellectual Property and Commercial Court (the "IP Court") stated in its 2016 Xing-Zhuan-Geng-(Yi) No. 4 Judgment that, "after the citations in the case are established, the technical level of a person having ordinary skill in the art will usually naturally emerge accordingly, and it is not necessarily required (nor, in fact, necessarily possible) to describe that technical level in a specific passage of text." The Supreme Administrative Court also affirmed this view in its 2020 Shang-Zi No. 575 Administrative Judgment, holding that a "person having ordinary skill in the art" is a hypothetical role whose attributes may gradually emerge through the parties' arguments. For example, when the parties dispute whether the claimed invention of the patent at issue differs significantly from the citations, or whether it produces significant effects compared with the citations, that dispute is part of the process of concretizing the technical ability of the person having ordinary skill in the art. The logic of the omission view is roughly as follows: assume that the patent at issue concerns a feeding device intended to solve the problem of pushing out multiple articles at one time. Citations A and B are also feeding devices and are likewise intended to solve the problem of pushing out multiple articles at one time. Because the two citations belong to the same technical field and share commonality in the problems to be solved, it may thus be inferred that a person having ordinary skill in the art could have easily thought of combining Citations A and B to arrive at the patent at issue. The patent at issue therefore lacks inventive step. When the court examines whether the citations have relevance in the technical field, commonality in the problem to be solved, commonality in function or effect, or any teaching or suggestion, and whether any factors supporting inventive step are present, the court has also, at the same time, considered whether a person having ordinary skill in the art could have easily conceived of such an invention. In fact, hindsight bias is inherently difficult to avoid in patent litigation. In a patent infringement action, the inventor is a concrete and identifiable person, and the invention claimed in the patent at issue has already been made. The defendant breaks down the patent at issue into technical features A, B, and C, searches patent databases worldwide, and finds three citations in the patent databases of China, Japan, and the United States corresponding to A, B, and C. When combined, they result in the invention claimed in the patent at issue. Yet the law requires the judge to disregard the plaintiff appearing before the court, assume a hypothetical person having ordinary skill in the art, disregard the actual result of the combination, and imagine whether, before the filing date, that hypothetical person would have had a motivation to combine Citations A, B, and C. Faced with a real inventor and an actual combined result, namely the patent at issue, the hypothetical reconstruction of time and space appears pale and powerless. It is therefore not difficult to understand why the Taiwan Intellectual Property Office and the IP Court, which are principally responsible for determining inventive step, have been quite receptive to the omission view. However, the prevalence of the omission view has fostered hindsight bias. In Taiwan patent infringement litigation, the rate at which invention and utility model patents are declared invalid by the courts is as high as 72.6% (cited from "The Current Practice of Taiwan Patent Infringement Litigation: A Collapsing Intellectual Property Ecosystem in Urgent Need of Rebirth," by Associate Professor Su-Hua Lee, The Taiwan Law Review, Issue 289, p. 130). Behind this figure lies a systemic problem that Taiwan's patent adjudication system has been unable to remedy for many years. The IP Court often uses a "mosaic-style" approach, piecing together and comparing citations. Once it finds that the technical fields are closely related and the problems to be solved are the same, it concludes that the patent lacks an inventive step. As to whether a person having ordinary skill in the art could have easily conceived of the invention, it is a question that may simply be omitted, or said to have naturally emerged. Of course, there are also cases in which the technical fields are closely related and share common problems to be solved, yet the court still found no reason to combine. For example, in the Intellectual Property and Commercial Court 2022 Xing-Zhuan-Su No. 20 Judgment, the court held that there was no motivation to combine because the citations involved different modes of mechanical operation. Such judgments, however, are exceedingly rare. In a rare instance, the Supreme Court 2024 Tai-Shang-Zi No. 453 Civil Judgment recently introduced the "Could-Would" approach in an attempt to bring this long-neglected legal requirement back into focus, and reversed and remanded the original judgment on this ground. In Part 2, we examine what the Could-Would approach actually requires — and why, without further refinement, it may not be enough to shake the deeply rooted adjudicative habits described above. The above views are the author's personal views and do not represent the position of the firm. Attorney Yi-Ta Tsai 2026/09/02 For further information regarding Deferred Examination, please feel free to contact us via email (jawhwa@jaw-hwa.com.tw). |