A. C concluded a sales contract (hereinafter “instant sales contract”) with Defendant D Co., Ltd. (the foregoing company was merged with the Defendant on November 24, 2015; hereinafter “Defendant, regardless of whether it was prior to the merger”) to sell one-half (hereinafter “each of the instant shares”) of the E forest land E 50,380 square meters and the F forest land 3,305 square meters (hereinafter “each of the instant real estate”), respectively, in Kimhae-si, and on February 1, 2013, with Defendant deposit and the intermediate payment of KRW 190,000,000,000,000 won, an intermediate payment of KRW 51,50,000,000,000 won, the balance of KRW 90,000,000,000,000 won, and the total amount of KRW 1.6 billion.

B. In the column for the special terms of the instant sales contract, the phrase “the remainder amount shall be KRW 900 million after the purchaser obtained permission for intermediate waste disposal business and received a loan for financial rights.”

C. The Defendant: (a) KRW 190 million for down payment on February 1, 2013; (b) KRW 110 million for the first intermediate payment on the 14th of the same month; (c) KRW 200 million for the second intermediate payment on May 2, 2013; and (c) the same month.

3. The third intermediate payment of KRW 200 million was paid, and the additional KRW 200 million was paid on April 1, 2015.

C received the second intermediate payment on May 2, 2013, and thereafter, upon completing the registration of ownership transfer with respect to each of the instant shares, C was established with the maximum debt amount of KRW 900 million with respect to each of the instant real estates, as the Defendant completed the registration of ownership transfer.

E. On April 1, 2015, C transferred the remainder claim under the instant sales contract (hereinafter “instant remainder claim”) to G (hereinafter “transfer of claim”), and on April 2, 2015, C completed the registration of establishment of the right to collateral security with respect to each of the instant real estate on the ground of the said transfer of claim in the future on April 2, 2015.

F. On August 7, 2017, G transfers to the Plaintiff a claim for interest in arrears calculated by the rate of 5% per annum from September 9, 2015 to August 7, 2017 on the instant claim (hereinafter “claim for interest in arrears of this case”) and (hereinafter “Assignment of Claim 2”) and on the same day, Article 2.