A. The status of the parties 1) Defendant School Foundation B (hereinafter “Defendant B Educational Institute”)

) In order to relocate B High Schools in Daegu-gu to Daegu-gu D, Daegu-gu, the construction work of the construction work of B High Schools (hereinafter referred to as “the construction work of this case”).

(1) The order holder is the Korea-Japan Construction Co., Ltd. (hereinafter “Korea-Japan Construction”).

(2) The Plaintiff was awarded a subcontract for reinforced concrete construction among the instant construction works (hereinafter “instant reinforced concrete construction”).

3) Defendant Construction Mutual Aid Association guaranteed the contractor’s duty to pay the subcontract price for the construction. B. (1) On April 20, 201, Defendant Research Institute concluded a contract for the construction of the instant construction by setting the total contract amount of KRW 24,191,00,000, and the construction period from August 9, 201 to January 30, 201, on the ground that the joint supply and demand between the Defendant Research Institute and the Korea-Japan Construction Co., Ltd. (hereinafter “FF”) and the U.S. Comprehensive Construction Co., Ltd. (hereinafter “U. integrated construction”).

2) On April 20, 201, Yangyang concluded a guarantee agreement for construction performance between the Defendant Construction Mutual Aid Association and the Defendant Construction Mutual Aid Association with regard to the instant construction amounting to KRW 4,797,80,000, contract amounting to KRW 23,989,00,000, contract amounting to KRW 20,000, and the contract execution date of April 30, 2012, and the guarantee period from April 20, 2011 to April 30, 2012. In special cases, the guarantee performance company of the instant construction is one-day construction, and the guarantee performance company can replace the guarantee performance by paying the guaranteed amount if it is impossible to execute the guarantee, and if the prime contract is a construction project, the guarantee performance company can replace the guarantee performance by the actual completion date of the construction project, notwithstanding the guarantee period, is deemed valid until the actual completion date of the construction project (Article 5(1)3).