1. The defendant's appeal is dismissed.

2. The costs of appeal shall be borne by the Defendant.

Purport of claim and appeal

1...

1. The reasons for the court's explanation concerning this case are as stated in the reasoning of the judgment of the court of first instance, except for adding the following judgments as to the defendant's argument added in the court of first instance, thereby citing it in accordance with the main sentence of Article 420 of the Civil Procedure Act.

2. Additional determination

A. Even though the guaranteed obligation based on the judgment of the court of first instance against the defendant of the non-party company (hereinafter "the guaranteed obligation of this case") is subordinate to the principal obligation based on the judgment of the court of first instance against the defendant of the non-party company (hereinafter "the principal obligation of this case"), the plaintiff, despite being aware that the principal obligation of this case was extinguished by prescription, denies the subsidiary nature itself and approved the above guaranteed obligation against the defendant, so the plaintiff cannot be viewed as having extinguished the guaranteed obligation of this case on the ground that the prescription period of the principal obligation of this case has expired.

B. Even if the extinctive prescription of the principal obligation is not completed due to such reasons as suspending the extinctive prescription of the principal obligation, if the extinctive prescription of the principal obligation is completed due to the completion of the extinctive prescription, the principal obligation is naturally extinguished due to the completion of the extinctive prescription, and thus, the guaranteed obligation also extinguished according to the nature of the principal obligation (see, e.g., Supreme Court Decisions 78Da2157, Feb. 13, 1979; 201Da78606, Jan. 12, 2012). Furthermore, even if the surety performed or approved the guaranteed obligation upon expiration of the extinctive prescription of the principal obligation, the waiver of the extinctive prescription of the principal obligation by the surety’s act, other than the principal obligor, cannot be deemed to have an effect on the waiver of the extinctive prescription of the principal obligation. Barring any other special circumstances, such as where the surety expresses his/her intent to discharge the guaranteed obligation despite the expiration of the extinctive prescription

Supreme Court Decision 200