As to the standard for determining the parties, the theories include the intention theory and the conduct theory, the indication theory (the prevailing view), and the normative classification theory, and court precedents adopt the substantive indication theory among them. Most of the indication theory appearing in current court precedents is a modified indication theory, under which the parties are to be determined by taking into account overall not only the statement of the parties in the complaint but all of its contents, including the purport and grounds of the claim.

Since the court takes the position of the substantive indication theory, determining the parties by considering the entire purport of the grounds of the claim and so on, Byeong, not A, who has nothing to do with the case, will be the true party to this case.

Where the names stated in the complaint are accurate but a third party litigates by usurping another person's name, for example where the usurper simply files suit in the name of the person whose name is usurped and conducts the litigation (usurpation on the plaintiff's side), or where, in a suit concerning the person whose name is usurped, the usurper simply impersonates that person's name and conducts the litigation (usurpation on the defendant's side), this is called name-usurpation litigation. (Choi Woo-jin, "The Discretion of Fact-Finding Courts in Calculating Damages," doctoral dissertation, Korea University Graduate School, 2018, Seoul)

Gap did not, without authority, usurp the defendant under A's name; rather, Gap intended to sue Byeong while clearly aware that the defendant was Byeong, and filed suit trusting the information received about another person's name as it was. This therefore differs from name-usurpation litigation, in which one acts as if one were the plaintiff or the defendant.

In this case, Gap filed a suit for damages against A based on the personal details received from Byeong, but the defendant Gap actually intended was Byeong and A is an unrelated person, so a question of determining the party arises. Under the courts' substantive indication theory, the defendant in this case is Byeong.

Our Civil Act adopts the principle of fault liability for liability for damages, and Article 750 of the Civil Act provides that "a person who causes losses to or inflicts injuries on another person by an unlawful act, intentionally or negligently, shall be liable to make compensation for damages arising therefrom," so the victim must prove the wrongdoer's intent or negligence to claim damages. Here, damages can be divided into positive damages such as medical and other expenses, negative damages, and damages for mental suffering. Mental damages are included within the scope of damages because they are understood not only as damage to property but as an infringement of personality rights.

Territorial jurisdiction is a requirement of the suit, so if a suit is filed with a court lacking jurisdiction, the court does not dismiss it but transfers it to the court with jurisdiction (Civil Procedure Act Article 34). In addition, if the defendant pleads on the merits without raising lack of jurisdiction, jurisdiction by pleading arises, and if the parties agree in writing, jurisdiction by agreement is also recognized. Organizing these jurisdiction rules together with the indication theory for determining parties and the effect of judgments in name-usurpation litigation lets you explain accurately, in civil procedure case questions and everyday-law assignments, where and against whom to start a lawsuit.