A. On March 19, 2016, the Plaintiff entered into a construction contract with D (hereinafter “principal debtor”) with the chairperson of the promotion committee representing the C Housing Association Promotion Committee of the Korea Housing Association of the Republic of Korea (hereinafter “C Housing Association Promotion Committee of the Korea Housing Association”). The Plaintiff jointly and severally guaranteed the Plaintiff’s obligation to pay the construction price to the Plaintiff by setting the construction period from March 19, 2016 to April 2016, with the construction cost of KRW 2,117,390,00 (i.e., construction cost of KRW 1,924,90,900,000, value-added tax of KRW 192,490,000), and the construction period of KRW 1,924,90,000).

(hereinafter) The said new construction project “instant construction project” and the said construction contract “instant contract,” and the project promoted by the said housing association or the promotion committee of the housing association (hereinafter “instant project”).

Article 5 of the contract of this case provides that "20% of the contract amount (the time when 20% members are recruited) shall be paid, 40% of the contract amount shall be paid when 40% of the contract amount is recruited after completion of 40%, and 40% of the contract amount shall be paid when members are recruited after completion of 60% of the contract amount after completion of 40% of the contract amount." The lower part of Article 5 provides that "80% of the total construction cost shall be paid at the time when 6 months have elapsed after commencement of the contract," and the signature and seal of both the plaintiff and the defendant shall be affixed thereto."

(hereinafter referred to as "the foregoing change of the repayment period agreement"). In addition, at the end of the above contract, the seal of the plaintiff and the principal debtor who are the party to the contract are affixed respectively to the contract, and at the end of the contract attached to the above contract, the seal of the defendant, a joint guarantor, affixed thereto.

C. Since then, the construction cost of the instant contract was reduced to KRW 1,936,498,734 (i.e., value 1,760,453,395 value-added tax of KRW 176,045,339).

The Plaintiff commenced construction of this case around May 2016 and around September 9, 2016.