1. The Defendant shall pay to the Intervenor succeeding to the Plaintiff KRW 559,440,100 and the interest rate of KRW 15% per annum from December 13, 2017 to the date of full payment.

1. Basic facts

A. Around March 2013, C agency announced the tender of D Corporation (hereinafter “instant Corporation”) with Defendant as an end-user institution (hereinafter “instant entity”).

The plaintiff was selected as a final successful bidder by participating in the bidding as a joint contractor (the share ratio: plaintiff 51%, E 49%) with E Co., Ltd. (hereinafter referred to as "E").

(hereinafter referred to as "the plaintiff, etc." in combination with the plaintiff, E).

Plaintiff

On April 24, 2013, between the Defendant and the Defendant, the total construction price of KRW 18,093,546,00 and the total construction period of the instant construction works shall be 0.1% of the contract price for delay from April 30, 2013 to December 9, 2016, and the contract price for delay shall be 13,527,72,200, and the construction period of the instant construction works shall be 13,527,72,200 among them, and the construction contract was concluded from April 30, 2013 to April 28, 2016.

(Contract Number:F) The First Number Corporation was changed by six times until August 9, 2016 as follows:

(Contract Number: G through H. The 2nd change on November 28, 2013, the first change on the date of completion of the contract (reasons for the change). The 2nd change on April 28, 2016, Oct. 14, 2014; 15,217, 972,000 won on April 15, 2015; 10,563,497,00 won on September 15, 2015; 30,00 won on April 28, 2016; 4th change on September 15, 2015; 30,00 won on April 28, 2016; 10,000 won on September 15, 2015; 30,730,730,700 won on September 16, 2018; 16.

C. On August 16, 2016, the Plaintiff changed part of the primary construction work to the secondary construction work according to J’s discontinuance of construction works, site conditions, etc. included in the details of the primary construction work, and requested the 5th revision of the primary construction work (the 7th revision of the contract) by reducing the construction cost of the primary construction work from 17,246,31,130 to 14,008,023,80 won.

On August 25, 2016, the responsible supervisor requested the defendant to approve the above design change, and the defendant is on the same day.