A. On June 30, 2016, Nonparty D and E Co., Ltd. (hereinafter “D and E”) entered into a subcontract with Nonparty F Co., Ltd. (hereinafter “F”) on a condition that the contract amount of the civil engineering works among the City Reconstruction G Co., Ltd. (hereinafter “instant construction works”) was set at KRW 3,969,063,774, and the contract period from June 30, 2016 to August 9, 2018.

B. Around July 2016, F entered into a subcontract agreement (hereinafter “instant subcontract agreement”) with respect to D, E, and the instant construction work. The Defendant, who succeeded to the instant construction work en bloc, entered into said subcontract agreement with respect to the terms and conditions of contract amounting to KRW 3,338,763,774 as to D, E, and the instant construction work, and the period from September 6, 2016 to August 31, 2018 (hereinafter “instant subcontract”).

C. Meanwhile, the Plaintiff, while running H, continued to receive a sub-subcontract from F to re-subcontract the part of the instant construction, and then concluded a re-subcontract with the Defendant as seen above by the Defendant succeeding the instant construction en bloc.

At the time, the construction cost of the household facilities was set at KRW 583,00,000 (including value added tax).

1) Around April 2017, the Plaintiff completed the instant construction work, and the Defendant completed the instant construction work on or around August 30, 2018. (2) The Plaintiff was paid KRW 572,50,000 in total as the construction cost from July 31, 2016 to August 11, 2017 by Defendant or D, and E.

E. On the other hand, on April 30, 2017, the Plaintiff issued an electronic tax invoice on KRW 31,186,650 as to the portion of KRW 21,286,650 in total, including KRW 9,900,00 for progress payment for facilities and KRW 21,286,650 for March 3, 201, and revoked the additional amount of KRW 21,286,650.

【Ground of recognition】 The fact that there is no dispute, Gap’s 3 through 5, Eul’s 1 through 3, Eul’s 4-1 through 7, Eul’s 5-1 and 2, and the purport of the whole pleadings

2. The assertion and judgment

A. The Plaintiff’s assertion 1 by the parties concerned is as follows: KRW 9,900,000 for March of the construction cost of the household facilities.