The difference between KIPO and EPO in the combination of inventions for inventive step assessment

Inventive step (non-obviousness) is one of the most important elements in determining the patentability requirements of an invention. South Korea and Europe have, in general, the same context in terms of whether the invention is obvious to be derived from the prior art(s) by a person skilled in the art. In terms of the combination of previously published inventions when assessing an inventive step, however, some differences have been captured between the Korean Intellectual Property Office (hereafter KIPO) and the European Patent Office (hereafter EPO). As a matter of fact, according to the Darts-ip database, approximately 8% of the total decisions from KIPO in 2019 discuss the combination of invention, whereas only around 1% of the decisions in EPO refer to the combination invention/juxtaposition.[1]

What makes this difference? In general, there is a distinction within the current practice in regard to patent examination. In accordance with the Patent Examination Guideline published by KIPO, it specifies several possibilities for determining the inventive step of the combining invention, one of which is the following: “the determination of whether a prior art disclosure contains a motivation, suggestion, or the like for a combination shall be made by synthetically assessing the following: whether the motivation, suggestion, or the like is explicitly taught in the prior art; whether the motivation, suggestion, or the like is inherent from the technical problem to be solved by the invention; or whether the motivation, suggestion, or the like is part of the common general knowledge or empirical rules of a person skilled in the art.” As stated directly in the guideline, KIPO often employs combining of prior arts for the assessment of non-obviousness.

As an example, let’s look at the latest case ruled by IPTAB (Intellectual Property Trial and Appeal Board) on 27-11-2019 (darts-993-496-H-ko). The patentee (plaintiff) argues that it is not obvious to combine those previous invention 1,2 because they have different purposes. Nevertheless, IPTAB concluded that “The prior art 1 and 2, as discussed earlier, not only have in common for use of two or more types of electrolyte salt as a mixture in order to solve the problem of using one type of electrolyte salt, but also the combination of electrolyte salt from prior art 1 is identical to Example 3 in the claimed invention, and also the combination of prior art 2 is identical to Example 2 in the claimed invention. Therefore, the plaintiff’s argument that combining two inventions 1,2 is not obvious from the different purpose shall not be accepted.”

In comparison, the approach to this matter in EPO is somewhat different. ‘Problem-Solution Approach (PSA)’[2] and ‘Could/Would Have Been Approach’ are generally used as the main criteria for the assessment of an inventive step. Although the EPO’s Guideline for Examination[3] mentions the combination of inventions, it implies the possibility of combination of inventions achieved from the problem-solving approach. In addition, it distinguishes ‘combination’ from ‘aggregation’. The former is namely a structurally meaningful sum of each feature as a whole, while the latter is a mere juxtaposition of each one. Most importantly, EPO emphasizes the ‘synergistic effect’ as follows:

A set of technical features is regarded as a combination of features if the functional interaction between the features achieves a combined technical effect which is different from, e.g. greater than, the sum of the technical effects of the individual features. In other words, the interactions of the individual features must produce a synergistic effect. If no such synergistic effect exists, there is no more than a mere aggregation of features.”

Let’s take another look at a recent case from the opposition division in EPO on 31-10-2019 regarding the determination of inventive step of the patent EP2968302. The judges argued that “It would not be obvious for the skilled person to add compound 2 to the combination of TM5 and expect an improved antiviral activity, let alone a synergistic effect…(omit)…even if the synergy was not considered in the formulation of the problem to be solved, a pangenotypic effect of the present combination in absence of interferon would still be a surprising effect. It would not be obvious to combine the present compounds and expect the claimed activity.” (darts-993-909-H-en)

Although the KIPO’s Patent Examination Guideline refers to ‘synergistic effect’ similar to those of the EPO’s in terms of combining previous inventions as follows, it is partial and not mandatory to do so in practice.

It is normally considered to be obvious to combine a well-known technology with another prior art disclosure. However, if a technical feature to be combined is a well-known technology in the art, but a combination with another technical feature results in an advantageous effect, the combination is not regarded as obvious.”

As such, there is a slight but clear difference between each patent office regarding the combining of prior documents for the inventive step. While KIPO views it from a broader perspective, EPO has a narrower view that emphasizes the advantage of the synergistic effect. If you wish to file a patent application with success, adopting a strategic behavior according to each patent office would be a shortcut to obtain your patent right.


[1] Search criteria: KIPO/European Instance, decisions (decision & order) from 01-01-2019 to 31-12-2019. Please note that there can be a slight error from some un-analysed cases.

[2] Each step is the following:

1) determining the “closest prior art”,
2) establishing the “objective technical problem” to be solved, and
3) considering whether or not the claimed invention, starting from the closest prior art and the objective technical problem, would have been obvious to the skilled person.

[3] Guideline for Examination, November 2019