The judgment below

The part against the Defendant is reversed, and that part of the case is remanded to the Seoul High Court.

The grounds of appeal are examined.

1. If there exists a seizure and collection order against the claim, only the collection creditor may institute a lawsuit for performance against the garnishee, and the debtor loses the standing to institute a lawsuit for performance against the seized claim;

(1) The court shall investigate and determine ex officio a matter to be examined and determined by the court, even if a party does not assert any of the parties to the case at an ex officio. The same shall also apply where the circumstances, such as the standing to sue, occur after the closing of argument in the fact-finding trial.

(see, e.g., Supreme Court Decisions 89Nu1308, Oct. 10, 1989; 2001Da51510, Mar. 26, 2004). 2. Reviewing the Defendants’ allegations in the grounds of appeal and records, the following facts are revealed.

① In relation to the instant construction project, the Plaintiff sought reimbursement of the construction cost around the Defendant, and filed the instant claim seeking restitution of unjust enrichment in the conjunctive interest.

② However, on January 6, 2017, which was after the date of the closing of argument in the lower court, the National Bank Co., Ltd. received the claim seizure and collection order by stating the debtor as the defendant, the third debtor as the defendant, the claim amounting to KRW 674,85,275, and the seized claim as the "amount from among the claims that the plaintiff is to receive from the defendant pursuant to the Seoul Central District Court Decision 2014Gahap927 and Seoul High Court Decision 2015Na2006935, Jan. 11, 2017 (the first instance judgment and the lower judgment)." The claim seizure and collection order was served on the defendant on January 11, 2017.

③ In addition, on January 12, 2017, after the date of the closing of argument in the lower court, Daesung Co., Ltd., the Plaintiff was based on the Seoul Southern District Court Decision 2017TTTTTT44, 977, 216 won, and the Seoul Central District Court Decision 2014Gahap927, Seoul High Court Decision 2015Na2006935, and Supreme Court Decision 2017Da200597, supra (the instant case).