A Complete Guide to Patent Claim Drafting Requirements In Korea

The value of a patent is determined by its "scope of claims." No matter how brilliant an invention is, it will lose its power as a legal right if the claims are poorly drafted. The scope of claims is the definitive part of a patent that establishes the boundaries of protection, and the Korean Patent Act stipulates strict formal requirements for how they must be written.

Failure to meet these requirements can lead to the rejection of a patent application or serve as grounds for invalidation even after registration. Today, we will take an in-depth look at the most fundamental yet crucial "formal requirements for claim drafting" as defined in Article 42(8) of the Patent Act and Article 5 of its Enforcement Decree.

[Article 5 of the Enforcement Decree of the Patent Act]

Article 5 (Method of Describing the Scope of Claims)① When drafting claims for the scope of claims pursuant to Article 42(8) of the Act (hereinafter referred to as "claims"), at least one independent claim (hereinafter referred to as an "independent claim") must be included. A dependent claim (hereinafter referred to as a "dependent claim") that limits or adds to the independent claim to provide further detail may also be included. In such cases, another dependent claim that further limits or adds to the preceding dependent claim may be included if necessary.② The number of claims shall be appropriate to the nature of the invention.③ Deleted④ A claim that cites another claim must state the number of the claim being cited.⑤ A claim that cites two or more claims must do so in the alternative.⑥ A claim citing two or more claims shall not be cited by another claim that also cites two or more claims. The same shall apply where a claim citing two or more claims is cited by a claim that cites a single claim, if that single claim ultimately relies on a citation of two or more claims.⑦ A cited claim must precede the citing claim.⑧ Each claim shall begin on a new line and be numbered consecutively with Arabic numerals in the order it is written.

1. Independent and Dependent Claims: The Foundation and Expansion of Rights (Enforcement Decree Article 5(1))

The scope of claims is composed of independent and dependent claims.

• Independent Claim: A claim that defines the right independently by listing all the essential constituent elements of the invention without citing any other claim. Every patent application must include at least one independent claim.
• Dependent Claim: A claim that cites an independent claim or another dependent claim to either limit its scope (e.g., moving from a broader concept to a narrower one) or add further components to specify the invention in greater detail. Dependent claims help to clarify the scope of the independent claim and provide flexibility during the examination process.

Key Point: A dependent claim must limit or add to the elements of a preceding claim. If a claim is formatted as a dependent claim but deletes or substitutes an element from the preceding claim, it is not considered a proper dependent claim.

[Simple Examples]

• [Claim 1] (Independent Claim) A chair comprising: a seat (A); and legs (B) for supporting said seat (A).
• [Claim 2] (Proper Dependent Claim - Addition) The chair of claim 1, further comprising a backrest (C) connected to said seat (A).
• [Claim 3] (Proper Dependent Claim - Limitation) The chair of claim 1, wherein said legs (B) are made of a metallic material.
• [Claim 4] (Improper Dependent Claim - Substitution) The chair of claim 1, comprising wheels (D) instead of said legs (B).(→ This is improper because it substitutes the "legs" element with "wheels.")

2. Number and Category of Claims (Enforcement Decree Article 5(2))

A single claim must describe only one category of invention. For example, an "apparatus" and a "method of manufacturing" that apparatus are different categories of invention and cannot be included in the same claim.

[Simple Examples]

• (X) Incorrect: [Claim 1] A smartphone comprising A, B, and C, and a method of manufacturing the smartphone.
• (O) Correct: [Claim 1] A smartphone comprising A, B, and C. [Claim 2] A method of manufacturing a smartphone comprising A, B, and C.

Additionally, you must not draft multiple claims that are literally identical.

3. Rules for Citing Claims (Enforcement Decree Article 5(4), 5(5), 7)

When drafting dependent claims or any claim that cites another, you must follow specific rules.

• Specify Citation Number (Clause 4): Instead of vague phrases like "In the preceding claim," you must clearly state the number of the claim being cited, such as "The invention of claim 1."
• Alternative Citation (Clause 5): When citing two or more claims, you must do so alternatively using terms like "or" or "according to any one of claims...". Conjunctive citation using "and" is not permitted.
• Citation Order (Clause 7): The cited claim must always appear before the citing claim. For instance, Claim 5 cannot cite Claim 8.

[Simple Examples - Alternative Citation]

• (O) Correct: The invention of claim 1 or claim 2, wherein...
• (O) Correct: The invention according to any one of claims 1 to 3, wherein...
• (X) Incorrect: The invention of claim 1 and claim 2, wherein... (→ This is improper as it could be interpreted as combining all features of both claims 1 and 2, violating the principle of alternative citation.)

4. The Pitfall of Multiple Dependent Claims (Enforcement Decree Article 5(6))

This is the most complex and error-prone area. A dependent claim that cites two or more other claims (a "multiple dependent claim") cannot serve as the basis for another multiple dependent claim. This rule exists to prevent the claim interpretation from becoming overly complex.

[Simple Example]

• [Claim 1] A writing instrument.
• [Claim 2] The writing instrument of claim 1, further comprising ink.
• [Claim 3] The writing instrument of claim 1 or claim 2, further comprising an external clip.(→ Claim 3 is a "multiple dependent claim" as it cites two claims. This is permissible.)
• (O) Correct: [Claim 4] The writing instrument of claim 3, wherein said clip is made of a metallic material.(→ This is permissible because it cites only one claim (Claim 3).)
• (X) Incorrect: [Claim 5] The writing instrument of claim 1 or claim 3, wherein the body has a hexagonal shape.(→ This is a violation of the requirements because it is a new multiple dependent claim (citing claims 1 and 3) that cites a previous multiple dependent claim (Claim 3).)

5. Claim Numbering and Format (Enforcement Decree Article 5(8))

These are fundamental requirements that must be followed.

• Each claim must begin on a new line.
• Claims must be numbered consecutively with Arabic numerals (1, 2, 3...) in the order they appear. No numbers should be skipped. (However, it is permissible for a number to be missing if a claim is deleted during a later amendment.)

Conclusion

The formal claim drafting requirements we have reviewed are the first step in defining the rights of a patent. A truly powerful patent is created only when the claims not only satisfy these formal rules but also accurately express the core idea of the invention and are strategically written to prevent competitors from designing around them.

Drafting optimal claims that account for complex regulations and numerous variables demands a high level of expertise. For a successful patent strategy, consult with the experts at Pine IP Firm. We will provide the highest quality legal services to transform your valuable ideas into the most robust and powerful rights possible.