A. The Plaintiff, around August 2015, entered into a sales contract with the Defendant and D to sell the ownership of the housing site from the Korea Land and Housing Corporation at KRW 145 million as the Plaintiff’s housing site was incorporated into the G development project district implemented by the Daejeon Seo-gu E and Fdong Korea Land and Housing Corporation (hereinafter “instant development project”). Around that time, the Plaintiff received the said sales contract from the Defendant.

B. On August 5, 2015, the Defendant: (a) as of August 5, 2015, in preparation for the case where D and D fail to perform their obligations under the instant purchase and sale contract, the Plaintiff, D and D acknowledged that D and D had the liability amount of KRW 400 million as of August 5, 2015 at the time of the Daejeon District Public Prosecutor’s Office, and decided to repay the said obligation (as of August 5, 2015, the date following the Defendant’s written request for payment) (Article 1 and 2); (b) as of the said obligation, the Plaintiff is jointly and severally liable for compulsory execution (Article 8); (c) as of August 5, 2025, when the Plaintiff and D fail to perform their obligations, D and D have the right to sell the said obligation to the Defendant for the purpose of securing the performance of the said obligation (Article 9); and (d) D, written a notarized deed stating that D transfer the right to sell the said obligation to the Defendant (Article 10).

C. D concluded a sales contract with the Korea Land and Housing Corporation on August 10, 2018, under which the instant development project was selected as a person eligible for supply of the said housing site, and that the Daejeon Sung-gu H 270 square meters (hereinafter “instant housing site”). D.

On October 4, 2018, the Defendant sent to D a written demand for payment of KRW 400 million of the obligation under the instant notarial deed to D immediately, and on October 8, 2018, the Defendant sent a written demand for payment of KRW 400 million.