Facts
Company A brought an invalidation action against another company in the Patent Court. The plaintiff was represented by a lawyer with 27 years in practice who, in a motion to reopen oral argument, cited eight AI-generated precedents that he had not checked. The episode came as the Korean judiciary was responding to fabricated AI citations. A task force of eight judges and two lawyers at the National Court Administration worked from November 2025 to March 2026. On 31 March 2026 it announced that courts could order parties relying on AI-fabricated statutes or case law to bear litigation costs, and could refer lawyers who failed to verify such material to the Korean Bar Association for discipline.
What was the legal question in Company A (anonymised) invalidation action?
The question was how a court should respond when a lawyer files non-existent precedents obtained from AI without checking them, and whether it should record this expressly in its reasoned judgment. Similar problems had already arisen with self-represented litigants, but here the fabricated citations appeared in a filing prepared by an experienced lawyer. That brought counsel's duty to verify authorities and duty of candour to the court directly into play.
What did the Patent Court of Korea decide?
In its judgment of 11 June 2026 the Patent Court stated expressly that many of the precedents the plaintiff relied on did not exist and that submitting them to the court without verification was inappropriate. It added to its reasoning that the plaintiff had admitted filing some judgments obtained through AI without checking them. Press reports do not state the outcome on the merits or whether the lawyer was referred for discipline. The anonymised judgment has not been published either, so it is not known whether the court attached any further legal consequence to this finding.
Why does Company A (anonymised) invalidation action matter?
The judgment is one of several reported in 2026 in which Korean courts expressly recorded that AI-generated fabricated precedents had been filed; here the party was represented by counsel. Read together with the measures the judiciary announced in March 2026, it shows the duty of lawyers using AI to verify their citations taking concrete form in court practice.
Related stages
Other courts made similar findings: the Suwon District Court (28 May 2026), the Seoul Eastern District Court (12 June 2026) and a civil division of the Daejeon District Court (11 August 2026).
The same question elsewhere
What follows from filing case law that AI made up?
The lawyers and their firm were sanctioned with a $5,000 penalty.
Mata v. Avianca, Inc.United Kingdom · 2025Referred to regulatorsThe lawyers were referred to their regulators; the court stressed the duty to verify.
R (Ayinde) v London Borough of Haringey; Al-Haroun v Qatar National Bank QPSC and QNB Capital LLCTürkiye · 2026Bar and prosecutor notifiedThe court wrote the same day; the disciplinary and criminal outcome is not yet known.
Yapay zekâ ile hazırlanan dilekçede hatalı Yargıtay künyeleriThe court stated in its judgment that unverified precedents relied on did not exist.
— this decision