1. The judgment of the first instance, including the Plaintiff’s claim expanded by this court, is modified as follows.

1. As long as the defendant's summary of the grounds for appeal was reasonable to resist the defendant's obligation to perform and its existence or absence, it is not right to determine the starting point of 15% interest per annum as provided by the first instance judgment on the day following the delivery date of the copy of the complaint in this case.

2. As a result of examining the grounds for appeal citing the judgment of the court of first instance and the evidence submitted by the parties, the court’s reasoning of the judgment of the court of first instance is as follows, since the reasoning for this case is stated in the main sentence of Article 420 of the Civil Procedure Act, except for the following portions, the court’s reasoning for appeal citing the judgment of the court of first instance is as stated in the reasoning of the judgment of first instance.

[Supplementary Use]

E. Accordingly, the Defendant is obligated to pay to the Plaintiff the interest or delay damages calculated at each rate of KRW 140 million per annum under the Civil Act from July 6, 2017 where the instant sales contract was impossible due to the sale of the instant land and the instant building to D, and at least 5% per annum under the Civil Act from September 12, 2018, which is the date of the final judgment of the court of first instance, to September 12, 2018, and the interest or delay damages calculated at each rate of KRW 15% per annum under the Act on Special Cases concerning Expedition, etc. of Legal Proceedings from the following day to the date of full payment.

[Plaintiff is claiming interest in arrears from February 23, 2016, which the Defendant received both down payment and intermediate payment according to the instant sales contract. However, a malicious beneficiary shall compensate for any loss incurred by returning the interest with the interest received (Article 748(2) of the Civil Act). If the beneficiary becomes aware that no legal ground exists after receiving the interest, he/she is liable to return the interest as a malicious beneficiary (Article 749(1) of the Civil Act). If the beneficiary loses a bona fide beneficiary, he/she is deemed a malicious beneficiary from the time of filing the lawsuit (Article 749(2) of the Civil Act).