1. The defendant's KRW 4,077,390 for the plaintiff and 5% per annum from July 7, 2020 to December 17, 2020 for the plaintiff.

1. Basic facts

A. On August 1, 2016, the Plaintiff, upon the introduction of C, sold to the Defendant KRW 57,329 square meters of D forest and E forest and 944 square meters of land (hereinafter “each of the instant real estate”) in Gangseo-gu, Busan (hereinafter “instant sales contract”), and the instant sales contract written between the Plaintiff and the Defendant, signed between the Plaintiff and the Defendant, with the payment of KRW 300,000,000 of the down payment of KRW 800,000 on the date of the contract, and the remainder of KRW 50,000,000 on the date of the contract, and the remainder of KRW 50,000,000 on the date of the remainder of the contract, was paid to the Defendant’s acquisition of the secured debt arising out of the establishment registration of a mortgage association, and the debtor F (the Plaintiff’s wife).

B. On August 1, 2016, the Plaintiff received KRW 200,000,000 from the Defendant from the Defendant and completed the registration of ownership transfer concerning each of the instant real estate on the same day.

C. On October 21, 2016, the Defendant paid KRW 15,000,000 to the Plaintiff via C.

[Ground of recognition] Facts without dispute, entries in Gap evidence 1, 2, 3, and 6 (including those with several numbers), the purport of the whole pleadings

2. The plaintiff's assertion

A. The Plaintiff sold each of the instant real estate to the Defendant through the instant sales contract at KRW 800,00,000. The Plaintiff received from the Defendant only KRW 200,000 on the day of the contract, including KRW 15,00,000 on October 15, 2016, and KRW 215,000,000 on October 21, 2016. 2) In addition, even though the Defendant intended to take over the secured obligation of the right to collateral security established on each of the instant real estate in lieu of the remainder of KRW 500,00,000, the Defendant acquired the secured obligation for the remainder of KRW 500,000, later than one year, and the Plaintiff assumed KRW 4,07,390 on the aggregate as the interest on the secured obligation of the said right to collateral security after the instant sales contract.

3) Therefore, the Defendant paid to the Plaintiff the remainder of KRW 85,000,000 for the purchase price (= KRW 800,000,000 for the purchase price - down payment of KRW 215,00,000 for the right to collateral security (right to collateral security) that the Defendant acquired, and the Plaintiff paid by proxy.