1. Of the judgment of the court of first instance, the main claim of the Plaintiff (Counterclaim Defendant) to be changed and added in the trial.

1. Scope of the judgment of this court;

A. In the first instance court, the plaintiffs, as the principal claim, filed a claim against the defendant D, ① as the principal claim, ② as the main claim, as the completion of the contractual obligation, or as the main claim under Article 538(1)1 of the Civil Code, each claim for the agreed amount based on the rate of performance. ② In preparation for the case where the claim against the defendant D is dismissed, the plaintiffs filed a preliminary claim against the defendant E for the agreed amount pursuant to Article 538(1)1 of the Civil Code, the completion of the contractual obligation, the claim for the agreed amount pursuant to Article 538(1)1 of the Civil Code, and the preliminary claim for the agreed amount based on the rate of performance. The defendant D claimed a penalty as the counterclaim, and the court of the first instance rendered a judgment dismissing both the plaintiffs’ main and main claim and the counterclaim.

B. As to this, only the plaintiffs appealed against the main claim against the conjunctive defendant E in the judgment of the first instance. However, in the case of subjective preliminary co-litigation, if an appeal is filed against any of the primary co-litigants and the conjunctive co-litigants, the part of the claim against the other co-litigants shall also be subject to the judgment of the appellate court. In such a case, the subject of the judgment of the appellate court shall be determined by taking into account the necessity of the consolidated conclusion of the conclusion between the primary co-litigants and their other parties (see, e.g., Supreme Court Decisions 2006Du17765, Mar. 27, 2008; 2009Da4355, Feb. 24, 2011). Thus, the judgment of the appellate court was rendered by the plaintiff's appeal against the primary defendant Eul as well as the main claim against the primary defendant Eul by the plaintiff's preliminary co-litigants, and the scope of the judgment of the appellate court becomes a final and conclusive judgment.

C. Meanwhile, in the trial of a party, the Plaintiffs seek the amount of the claim as a part of the claim, by reducing the claim of the previous main and conjunctive claim against the Defendants.