Which claim formats does Korea accept?

Chanjoong Kim, Partner · Published 26 October 2026

Last verified 9 October 2026

How each claim format is treated, at a glance

As of October 2026. “Guidelines” means the Patent Examination Guidelines of the Ministry of Intellectual Property (MOIP, 지식재산처).

A claim must show whether it is a product claim or a method claim

The Korean Patent Act has three categories of invention. Article 2, subparagraph 3 defines “working” separately for a product invention, a method invention and an invention of a process for manufacturing a product. [1]

The Guidelines determine the category of a claim from the term at the end of the claim. In principle, the closing term or expression decides whether the claim is a product claim or a method claim. If the category is still hard to determine after the substance of the invention is examined, the claim is judged to be unclear. [3]

Within a category, the manner of expression is free. The Guidelines state that a product invention can be expressed in various ways that describe structure, function or combination. A method invention can likewise be expressed in various ways that describe a method, an act or an operation. [3]

Article 42(6) of the Patent Act has the same purpose. The claims state the structure, method, function, material or combination of these that is needed to specify the invention. [1] The Guidelines state that a notice of grounds for rejection must not be issued on the basis of this provision. [3]

Article 2, subparagraph 3 of the Patent Act has no category called “use”. [1] The principle above also applies to a claim that ends like “use of substance X”. If the closing expression does not show whether the claim is a product claim or a method claim, the claim is unclear. [3]

One claim states an invention in one category. The Guidelines give the case where one claim states two or more inventions in different categories. The same applies where one claim has two or more subjects. In both cases a notice of grounds for rejection can be issued under Article 5(2) of the Enforcement Decree of the Patent Act (특허법 시행령). [2][3]

Several independent claims in the same category are not barred. Article 5 of the Enforcement Decree has no paragraph that sets the number of independent claims per category. [2] The Guidelines state that one application can contain several independent claims in the same category. [3]

Two requirements still apply. First, claims must be stated in a reasonable number according to the nature of the invention (Enforcement Decree, Art. 5(2)). The Guidelines give claims with identical wording stated more than once as an example of a violation. [2][3] Second, Article 45 of the Patent Act applies. The claims must be a group of inventions that form a single general inventive concept. [1]

Jepson type claims and functional limitations are not rejected for format alone

The Jepson type, divided into a preamble and a body (characterising portion), can be used in Korea. The Guidelines state that the form in which a claim is written does not change its technical scope. A Jepson type claim is also specified by the whole claim, including the preamble. [3]

An element is not treated as publicly known only because it is stated in the preamble. The Guidelines state that it is not appropriate to find an element publicly known from the preamble alone. The elements of the body must also not be separated and compared with the prior art on their own. [3]

There are cases, however, where an element in the preamble is presumed in fact to be publicly known. This is the holding of the Supreme Court of Korea (대법원) in Supreme Court en banc Decision 2013Hu37 Decided January 19, 2017. The presumption applies where it can be found that the applicant stated the element in the preamble as being publicly known art. The Supreme Court decides this from the specification as a whole and the prosecution history. [11]

This presumption can be rebutted. The same decision gives the example of an unpublished earlier application or in-house technology that was stated as publicly known by mistake. [11] The Guidelines take the same position on the background art. Art that the applicant has admitted to be publicly known in the specification or in a written argument is presumed in fact to be publicly known. [3]

Functional limitations are allowed under a condition. The Guidelines state that a claim with a functional limitation cannot be allowed unless the configuration of the invention is clear as a whole. [3]

The Guidelines give two cases, among others, in which the claim is found to be clear. One is where a functional limitation is needed because conventional technical features alone cannot clearly express the technical idea. The other is where the meaning of the functional limitation can be clearly determined from the description of the invention and the drawings. [3]

If the matter for which protection is sought cannot be clearly understood, there is a ground for rejection. The examiner takes into account the description of the invention, the drawings and the common general technical knowledge at the time of filing. If the examiner finds that the matter cannot be understood, a notice of grounds for rejection is issued for violation of Article 42(4), subparagraph 2 of the Patent Act. [3]

In the assessment of patentability, an element stated by its function is in principle interpreted as covering every invention that has that function. This is the holding of Supreme Court Decision 2007Hu4977 Decided July 23, 2009. Where the description of the invention or the drawings define or explain the term, the element is interpreted by considering its technical meaning. [7]

Functional limitations also raise the support requirement. The Guidelines give the case where a claim is stated as a “means” or a “step” that performs a specific function. If the description of the invention has no specific configuration that corresponds to it, the claim is of a type that is not supported (Patent Act, Art. 42(4), subparagraph 1). [1][3]

A product-by-process claim is treated as a product invention

Korea accepts product claims that state a manufacturing method. The Guidelines state that a product claim can be written in the form “a product manufactured by the method of …”. If the configuration of the product is clear as a whole, there is no deficiency in the description only because the claim contains a method feature. [3]

The claim is still examined for clarity. The Guidelines state that a ground for rejection under Article 42(4), subparagraph 2 of the Patent Act can be notified where the manufacturing method stated in the claim is unclear. The same applies where the claim is so unclear that the structure or properties of the product cannot be understood. [3]

The second ground for rejection can be overcome by proof from the applicant. The Guidelines give two cases. One is where the applicant proves special circumstances, such as that the product can only be specified by that manufacturing method. The other is where the applicant proves that the manufacturing method has no effect on the structure or properties of the product. [3]

Patentability is assessed on the product, not on the manufacturing method. This is the holding of Supreme Court en banc Decision 2011Hu927 Decided January 22, 2015. The product that has the structure or properties specified by all the statements in the claim, including the manufacturing method, is compared with the prior art. [4]

This decision does not distinguish whether or not the product can only be specified by its manufacturing method. The Supreme Court held that the meaning of the manufacturing method is not interpreted differently in either case. The decision overruled earlier decisions that took a conflicting view. [4]

A new manufacturing method is therefore not enough. The Guidelines give the case where the manufacturing method affects only production efficiency or yield. In that case, the product itself, without the manufacturing method, is taken as the subject of the novelty assessment. [3]

The same interpretation applies at the infringement stage. This is the holding of Supreme Court Decision 2013Hu1726 Decided February 12, 2015. There is an exception where the result is clearly unreasonable, for example where the scope of the right is too broad in light of the substance of the invention. In that case, the scope of the right can be limited to the scope of the manufacturing method stated in the claims. [5]

Markush type claims and parameter features have requirements

A Markush type claim is allowed if the whole invention after substitution has similar properties or functions. The Guidelines give the form “A + (any one of a, b and c)” as an example. [3]

A Markush type claim to chemical substances is accepted if it meets both of two requirements. First, all the chemical substances must have a common property or activity. Second, they must share an important chemical structural element or belong to a class of chemical substances recognised as one group. The Guidelines state that other technical fields, such as mechanical and electrical fields, are assessed in the same way. [3]

A parameter invention in the Guidelines is an invention that has, as an element, a parameter created by the applicant at its own choice. Parameters that are standard or commonly used in the technical field are not included. [3]

A parameter invention is treated as clearly stated only if four points can be understood. They are the definition or technical meaning of the parameter, the measuring method and measuring conditions, the reason why the parameter has to be used, and the relationship with the state of the art at the time of filing. [3] Even if these points are not stated in the description of the invention, the claim is not regarded as unclear if they are clearly understood from the common general technical knowledge at the time of filing. [3]

The Guidelines give examples of expressions that make the configuration of the invention unclear. [3]

These expressions are not always a ground for rejection. The Guidelines do not treat them as unclear if their meaning is clearly supported by the description of the invention and there is no problem in specifying the invention. [3]

There is also a case in which the Supreme Court found a transitional phrase in a claim to be unclear in that case. It is Supreme Court Decision 2007Hu1442 Decided October 11, 2007. It is a decision in a case on a decision of rejection, and the Supreme Court reversed the lower judgment and remanded the case to the Patent Court. The law applied is the former Patent Act, Art. 42(4), subparagraph 2, as it stood before the amendment of 3 January 2007. The application was an international patent application filed in a foreign language. After filing the translation, the applicant amended that part to “포함하는” (comprising) and received a decision of rejection. In the amendment made after filing an appeal against the examiner’s decision to reject a patent application (trial on rulings rejecting patent applications), the applicant wrote “필수적으로 이루어지는(consisting essentially of)”. In that case, the Supreme Court found that even the Korean part alone can be read in two ways. It also found that, in light of the attitude of the applicant shown in the notices of grounds for rejection and the course of amendment, the English stated alongside in parentheses, which at first sight conflicted with the applicant’s argument before the lower court, made the meaning of the Korean part even more unclear. The Supreme Court held that that part was a deficiency in the description. There is no sentence in the written judgment stating that expressions translating “consisting essentially of” are unclear in general. [12] This decision is covered separately in “Supreme Court Decision 2007Hu1442 Decided October 11, 2007: what circumstances did the Court rely on in finding a claim reading “필수적으로 이루어지는(consisting essentially of)” unclear in Korea?”.

A claim that refers to the description of the invention or the drawings is unclear in principle. The Guidelines accept it only where the feature cannot be properly stated without the reference. The example is an alloy whose composition is specified by the range enclosed by points in a drawing. [3]

Methods of treatment and a program as such are not accepted

A method of surgery, therapy or diagnosis of humans cannot be patented in Korea. The Guidelines call such a method medical practice and treat it as not being an industrially applicable invention. [3] Industrial applicability is a requirement of the main clause of Article 29(1) of the Patent Act. [1]

A treatment method that is not carried out by a medical practitioner can be treated in the same way. The Guidelines give treatment methods for curing or preventing human disease. They also give treatment methods for improving or maintaining the state of health. These inventions are treated as having no industrial applicability. [3]

The same applies to a method that includes medical practice as one step. The Guidelines do not accept a method invention that includes medical practice as at least one step or as an inseparable element. [3]

Medical devices and medicines themselves are industrially applicable inventions. [3] A diagnosis-related method that does not include clinical judgment is also treated as industrially applicable. The Guidelines give methods of collecting data, such as physicochemical measurement, analysis and testing, as examples. [3]

The result changes if the subject is limited to animals other than humans. The Guidelines treat the invention as industrially applicable if that limitation is stated in the claims. [3]

Other cases of method-of-treatment claims are covered in a separate article, “Are method-of-treatment claims allowed in Korea?”.

A medical use is claimed as a product invention. The basis is Supreme Court en banc Decision 2014Hu768 Decided May 21, 2015. The decision held that a medical use invention cannot be allowed as a method invention directed to a method of treating humans as such. An invention that adds a medical use to a medicine, which is a product, is patentable as a product invention. [6]

The same decision held that the dosage regimen and dose can also be elements of the invention. This is the case where they are added, in a product invention of a medicine, together with the target disease or the efficacy. [6]

A general product claim with a limitation of use is interpreted as a product specially suited to that use. The example in the Guidelines is a “hook for a crane”. If the product is not specially suited only to that use, the limitation of use does not affect the novelty assessment. [3]

A computer program per se cannot be an invention. The Guidelines regard a program as no more than instructions for running a computer. [3]

A software invention can qualify as an invention in four forms. The condition is that information processing by the program is concretely realised by using hardware. [3]

The fourth form applies to applications filed from 1 July 2014. The Guidelines state when it starts to apply only for that form. [3]

Utility models have a different subject. A utility model registration covers a device relating to the shape or structure of an article or a combination of articles (Utility Model Act (실용신안법), Art. 4(1)). [8]

A format violation is a ground for rejection, and some violations are also grounds for invalidation

A problem with claim format can be a ground for rejection for violation of Article 42(4) or 42(8) of the Patent Act. Article 62, subparagraph 4 of the Patent Act provides for rejection of an application that does not meet the requirements of Article 42(3), 42(4) or 42(8) or of Article 45. [1]

Grounds for rejection are set out in Article 62 of the Patent Act, and grounds for invalidation in Article 133(1). Article 62, subparagraph 1 and Article 133(1), subparagraph 1 both list violation of Article 29. [1] For an application that is not an invention, the Guidelines cite the main clause of Article 29(1) in the notice of grounds for rejection. [3]

Article 133(1), subparagraph 1 lists violation of Article 42(4) and does not list Article 42(8) or Article 45. [1] Article 42(6) appears in neither Article 62 nor Article 133(1). [1]

Dependent claims are not mandatory. Article 5(1) of the Enforcement Decree requires independent claims to be stated and provides that dependent claims can be stated. [2] The Guidelines do not issue a notice of grounds for rejection on the basis of this paragraph. [3]

Not every claim written with a reference is a dependent claim. The Guidelines treat as an independent claim a claim that removes an element of the claim referred to or replaces it with a different element. [3] An independent claim can also be written with a reference to another claim to avoid repetition. The example is “a product manufactured by the method of claim ○”. [3]

A claim that refers to another claim states the number of the claim referred to (Enforcement Decree, Art. 5(4)). [2] This paragraph received its present wording through an amendment in force from 1 July 2013. The Addenda provide that it also applies to applications pending at the time of entry into force. [2]

The limits on references by multiple dependent claims are covered in a separate article, “Are multiple dependent claims allowed in Korea?“.

How Korea differs

Four points change when a European or US claim set is brought to Korea.

Claims that come from Europe can keep the two-part form. Article 5 of the Korean Enforcement Decree of the Patent Act neither requires nor prohibits that form. [2] Rule 43(1) EPC provides that, wherever appropriate, the characterising portion begins with a set expression. The expression is “characterised in that” or “characterised by”. [9]

The preamble under Rule 43(1) EPC is the place for the technical features that form part of the prior art. [9] In Korea, a statement in the preamble alone does not establish that an element is publicly known. However, if it is found that the applicant stated the element as being publicly known art, it is presumed in fact to be publicly known. [11]

Korea does not have the European limit on the number of independent claims. Rule 43(2) EPC limits more than one independent claim in the same category to three cases. They are a plurality of interrelated products, different uses of a product or apparatus, and alternative solutions to a particular problem. The third case applies only where it is inappropriate to cover the alternatives by a single claim. [9]

US law sets the interpretation of an element stated by its function in the statute. Under 35 U.S.C. 112(f), the element is interpreted as the corresponding structure, material or acts described in the specification and their equivalents. [10] The Supreme Court of Korea has taken as its principle, in the assessment of patentability, the interpretation that covers every invention that has that function. [7]

What applicants should do

• In general, we suggest checking, before filing in Korea, whether the closing term of each claim is a product or a method. A claim that ends with “use” is rewritten as a product claim or a method claim.
• We suggest reviewing at the translation stage whether a method-of-treatment claim can be changed into a product claim. We also check whether the original specification has a basis for the change.
• For an element stated by its function, we suggest checking whether the description of the invention has a specific configuration that corresponds to it. The reason is that, in the Korean assessment of patentability, such an element is in principle interpreted as everything that has that function.
• For a product-by-process claim, we suggest preparing on the basis of whether the product itself differs from the prior art. Adding a separate claim to the manufacturing method is also an option.
• In the preamble of a Jepson type claim and in the background art, we suggest stating as publicly known art only art that is in fact publicly known.
• We suggest resolving “about”, “preferably” and “and/or” before the claims are put into Korean. The same applies to the translation of “consisting essentially of”.
• Please confirm the claim structure of an individual case with your Korean agent.

FAQ

If a claim is written as a Jepson type claim in Korea, is the preamble treated as publicly known art?

Not only because the element is stated in the preamble. The Guidelines state that the invention is specified by the whole claim, including the preamble. [3] However, if it is found that the applicant stated the element as being publicly known art, it is presumed in fact to be publicly known. This is the holding of Supreme Court en banc Decision 2013Hu37. [11]

Is a product-by-process claim granted if the manufacturing method is new?

That alone is not enough. Patentability is assessed on the product specified by all the statements in the claim, including the manufacturing method (Supreme Court en banc Decision 2011Hu927). [4]

Can a computer program be claimed in Korea?

A program as such cannot be claimed. For applications filed on or after 1 July 2014, the form “a computer program stored in a medium” can qualify as an invention. The information processing must be concretely realised by using hardware. [3]

What happens to a claim to a method of treating humans?

It is not recognised as an industrially applicable invention. [3] A medical use can be claimed as a product invention of a medicine (Supreme Court en banc Decision 2014Hu768). [6]

Is a patent invalid if it was registered in violation of the claim drafting requirements?

A violation of Article 5 of the Enforcement Decree of the Patent Act is not, on its own, a ground for invalidation. Article 133(1), subparagraph 1 of the Patent Act lists violation of Article 42(4) and does not list Article 42(8). [1]

How DEFINE IP Law Firm handles this

DEFINE IP Law Firm checks the format of the claims when preparing a Korean filing or entry into the Korean national phase. The reference is the provisions of the Patent Act, the Enforcement Decree of the Patent Act and the Guidelines listed in the tables of this article. For questions about the claim structure of Korean applications, please write to contact@defineip.kr.

Sources

1. Patent Act (특허법), Act No. 21134, in force from 11 November 2025. Article 2, subparagraph 3; Articles 29(1), 42, 45, 62 and 133. https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
2. Enforcement Decree of the Patent Act (특허법 시행령), Presidential Decree No. 35809, in force from 1 October 2025. Article 5; Addenda (Presidential Decree No. 24645, 28 June 2013) Arts. 1 and 2. https://www.law.go.kr/법령/특허법시행령 (verified 9 October 2026)
3. Ministry of Intellectual Property (지식재산처), Patent Examination Guidelines (특허·실용신안 심사기준), MOIP Established Rule (지식재산처예규) No. 7, in force from 13 March 2026. Part 2, Chapter 4, 3., 4., 5. and 6.1 to 6.4; Part 2, Chapter 5; Part 3, Chapter 1, 3., 4.1.8, 4.2 and 5.1; Part 3, Chapter 2, 4.1.2 and 4.4(5). https://www.law.go.kr/행정규칙/특허·실용신안심사기준 (verified 9 October 2026)
4. Supreme Court of Korea (대법원), Supreme Court en banc Decision 2011Hu927 Decided January 22, 2015 (2011후927). https://www.law.go.kr/판례/(2011후927) (verified 9 October 2026)
5. Supreme Court of Korea (대법원), Supreme Court Decision 2013Hu1726 Decided February 12, 2015 (2013후1726). https://www.law.go.kr/판례/(2013후1726) (verified 9 October 2026)
6. Supreme Court of Korea (대법원), Supreme Court en banc Decision 2014Hu768 Decided May 21, 2015 (2014후768). https://www.law.go.kr/판례/(2014후768) (verified 9 October 2026)
7. Supreme Court of Korea (대법원), Supreme Court Decision 2007Hu4977 Decided July 23, 2009 (2007후4977). https://www.law.go.kr/판례/(2007후4977) (verified 9 October 2026)
8. Utility Model Act (실용신안법), Act No. 21065, in force from 1 October 2025. Article 4(1). https://www.law.go.kr/법령/실용신안법 (verified 9 October 2026)
9. EPO, European Patent Convention, Implementing Regulations, Rule 43. https://www.epo.org/en/legal/epc/2020/r43.html (verified 9 October 2026)
10. United States, 35 U.S.C. 112(f) (USPTO MPEP Appendix L, marked as last revised 9 March 2026), 37 CFR 1.75(e) (eCFR, as of 1 September 2026). https://www.uspto.gov/web/offices/pac/mpep/mpep-9015-appx-l.html , https://www.ecfr.gov/current/title-37/section-1.75 (verified 9 October 2026)
11. Supreme Court of Korea (대법원), Supreme Court en banc Decision 2013Hu37 Decided January 19, 2017 (2013후37). https://www.law.go.kr/판례/(2013후37) (verified 9 October 2026)
12. Supreme Court of Korea (대법원), Supreme Court Decision 2007Hu1442 Decided October 11, 2007 (2007후1442). https://www.law.go.kr/판례/(2007후1442) (verified 10 October 2026)