1. The Defendant (Counterclaim Plaintiff) paid KRW 33,191,753 to the Plaintiff (Counterclaim Defendant) and its amount from September 8, 2015 to August 10, 2017.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Basic facts

A. Around December 19, 2012, before the Plaintiff’s establishment, C, the representative director of the Plaintiff, consulted with the Defendant to accept a subcontract for KRW 620,00,000 from the Defendant for the metal works (hereinafter “instant works”) among D works (hereinafter “instant works”).

B. C lending the name of E (business title: F) and establishing the Plaintiff corporation. Around February 7, 2014, the Plaintiff increased the total construction amount to KRW 720,000,000 ( KRW 100,000,000 in the construction cost of the original contract amount of KRW 620,000,000) with respect to the instant construction project undertaken by C with the Defendant as the contract amount of KRW 305,887,649 (excluding value-added tax), which is the contract amount of the construction cost, excluding the completed construction amount.

C. After that, the Plaintiff discontinued the instant construction work on June 26, 2014. At the time, the total construction cost of the instant construction work, which was finally agreed upon between the original Defendant and the original Defendant, is KRW 744,085,794, and the total construction cost that the Defendant paid to the Plaintiff is KRW 644,668,382, and the construction cost agreed upon between the original Defendant and the non-execution cost is KRW 103,970,300.

[Ground of recognition] Facts without dispute, Gap evidence Nos. 2, 5, 7, 9, 10 (including branch numbers, hereinafter the same shall apply), Eul evidence Nos. 21, and the purport of the whole pleadings

2. The parties' assertion

A. The Plaintiff’s principal claim as to the instant construction project was executed in addition to the scope of the original construction project upon the Defendant’s request during the process of performing the instant construction project. The Defendant, as to the sum of KRW 1,780,312, and value-added tax on February 2, 2014, the amount of KRW 14,393,693 (hereinafter “the construction cost portion”), and KRW 151,140,000, deducted the remainder of KRW 158,60,714,05 from the sum of KRW 1,780, KRW 312,393,693, and value-added tax on February 2, 2014 (hereinafter “the said portion of the construction cost”).