1. The defendant,

A. As to KRW 2,130,662,220 among Plaintiff A Co., Ltd. and KRW 1,285,614,720 among them, June 20, 2017.

1. Basic facts

A. Status of the parties 1) Plaintiff A Co., Ltd. (hereinafter “Plaintiff A”).

(2) On June 4, 2018, Plaintiff B and Plaintiff B were companies running the construction business, and C were divided and established from Plaintiff B and succeeded to the rights and obligations regarding the intermediate industry construction business of Plaintiff B, and Plaintiff B transferred the instant lawsuit (hereinafter “Plaintiff B”) without distinguishing Plaintiff B and C, which is the party taking over the lawsuit thereof.

(2) The Defendant is a public institution to which the Act on the Management of Public Institutions (hereinafter “Public Institutions Operation Act”) applies as a corporation established for the purpose of contributing to the enhancement of convenience in people’s lives and the improvement of public welfare by laying the foundation for the stable long-term supply of gas in accordance with the Korea Gas Corporation Act.

B. 1) The Plaintiffs’ investment ratio is Plaintiff A75% and Plaintiff B25%, and the representative is Plaintiff A (hereinafter “instant joint supply and demand company”).

(E) On December 17, 2013, the term “D-E, F-G, and H-I main pipelines construction work” (hereinafter “instant construction work”) that establishes gas pipes underground for gas supply with Defendant on December 17, 2013.

As to the construction contract, the construction cost shall be KRW 73,411,260,761, and the construction period shall be from December 17, 2013 to October 31, 2015 (hereinafter “instant construction contract”).

(2) The part related to the instant case in general conditions of the construction contract incorporated into the instant construction contract (hereinafter “instant general conditions”) and special conditions of the construction contract and Class II of the special conditions of the construction contract (hereinafter “instant special conditions”), are as follows, except as otherwise provided in this case’s general terms and conditions, Article 2(10) of the Enforcement Decree of the Act on Contracts to Which the State is a Party, and the Act on Contracts to which the State is a Party.