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Evidence Collection for Patent Litigation in Korea

Pine IP Firm
October 1, 2026

Korean patent litigation does not provide broad US-style discovery. A patent owner should identify the accused conduct and assemble evidence for each asserted claim element before filing. Court procedures can then be used for specific evidence held by the defendant or a third party.

Organized evidence files for Korean patent litigation

Evidence for each claim element

For each asserted claim, the file should identify:

  • the accused product, process, version and relevant period;
  • the evidence supporting each claim element;
  • whether the evidence is public, available for purchase or testing, or held by the defendant;
  • the witness or record capable of authenticating it;
  • required translation or expert analysis; and
  • the court procedure available for evidence that cannot be obtained privately.

This analysis determines what should be purchased or tested and allows a submission request to identify the material and fact to be proved with reasonable precision.

Evidence obtained before suit

Product purchase and custody

Accused products should be purchased through ordinary Korean sales channels where possible. Preserve the product listing, order confirmation, invoice, packaging, serial number, delivery record and unboxing record. Retain an untouched sample and document transfers to counsel and experts.

Public technical material

Relevant material may include manuals, regulatory filings, certifications, product pages, videos, catalogues, patents, standards submissions, tender documents and archived webpages. Record the URL, access date and full context. A cropped or undated screenshot may be difficult to authenticate or interpret.

Testing and reverse engineering

Technical testing should follow a written protocol. The record should identify the sample, equipment, calibration, software version, method, raw data, assumptions and repeatability. Materials relied on by the expert may later need to be disclosed.

Third-party information

Customers, suppliers, former employees and distributors may have relevant information. Any contact must comply with confidentiality, employment, privacy and other applicable law. A party should not induce a breach of an NDA or misuse of a trade secret.

Original files, devices and samples should be retained. Analysis should be performed on documented copies where appropriate, with a record of each person who handled the evidence.

Court preservation of evidence

Under Korean civil procedure, a party may apply to preserve evidence before or during the main action when later examination may be difficult. Depending on the evidence, the court may examine a witness, inspect an object or site, review documents or conduct an appraisal.

The application must identify the evidence, the fact to be proved and the reason preservation is necessary. It is a specific evidentiary procedure, not a general search. A technical application should state what is to be inspected or preserved and how it relates to the asserted claim.

Orders to submit materials

Article 132 of the Patent Act allows the court, on a party's application in a patent or exclusive-licence infringement action, to order the opposing party to submit materials needed to prove infringement or calculate damages. Submission may be refused for a justifiable reason.

If the holder asserts a justifiable reason, the court may require the material to be shown privately for that determination. A trade secret is not by itself a justifiable reason when the material is indispensable to proof of infringement or calculation of damages. The court must then limit the persons or scope permitted to inspect the material.

An application should identify the material or category, likely holder, product and period, the claim element or damages issue, and the reason equivalent evidence cannot reasonably be obtained elsewhere. Under Article 132, failure to comply without justification may permit the court to accept specified allegations as true in the circumstances set out in the statute.

Specific statement of the accused conduct

Article 126-2 applies when a party denies the patent owner or exclusive licensee's specific allegation concerning the content, manner or form of infringement. The denying party must state its own specific conduct unless it has a justifiable reason not to do so.

The court may order submission of materials needed to determine whether the asserted reason is justified. If the party fails without justification to state its specific conduct, the court may accept the patent owner's specific allegation as true. The provision does not eliminate the claimant's initial obligation to allege the accused conduct specifically.

Inspection, appraisal and inquiries

Other procedures may include court inspection of products, facilities or records; expert appraisal; examination of witnesses or parties; inquiries to government bodies or third parties; and orders concerning financial records relevant to damages.

Each request should identify the fact to be proved. An expert can explain technical evidence but cannot supply facts that are absent from the record, and an inquiry should be limited to questions the recipient can answer.

Software and digital evidence

In a software case, preserve version-specific binaries, logs, API behaviour, user flows, network captures and device configuration. A request for source code should identify the relevant modules, functions, versions and claim elements rather than the entire repository.

Confidentiality measures may include restricted inspection, secure review environments, redaction, limits on copying and court orders. The arrangement must still allow the receiving expert to test the technical issue presented to the court.

Damages evidence

Damages evidence should be preserved with the infringement evidence. The patent owner's records may include sales, production capacity, margins, price effects, licence history and product-substitution evidence. The likely categories of the defendant's sales and accounting records should be identified early so that a later submission request is specific.

Article 128 provides several methods for assessing patent-infringement damages and permits the court to determine a reasonable amount when damage is established but exact proof is extremely difficult. For intentional infringement, the court may award up to five times the amount recognised as damages under the statutory methods. Evidence relevant to intent and the statutory factors should therefore be retained.

Evidence-management errors

Recurring problems include sending a warning before securing the product and online evidence, relying on undated screenshots, testing the wrong model or software version, losing the custody record, requesting overly broad categories, collecting personal or confidential data without authority, and using inconsistent product descriptions in the infringement action and an IPTAB trial.

Once litigation is reasonably anticipated, relevant records should be preserved under a written hold. A single index should record the source, date, custodian, version and purpose of each item.

Official references

Related South Korea IP guidance

This article provides general information. Evidence collection must be assessed under the facts of the case and applicable Korean procedure, privacy, employment and criminal law.

Legal and editorial review: July 16, 2026. Korea's current IP authority is the Ministry of Intellectual Property (MOIP), formerly KIPO.