A. The party-related Plaintiff is a corporation that runs a creative construction business or steel construction business, and the Defendant is a corporation that runs a housing construction business, interior decoration business, etc.

B. On October 4, 2016, C Co., Ltd. (hereinafter “C”) entered into a contract for construction works between C and the Defendant (hereinafter “instant construction”) with the Defendant and the Defendant, set the tax exemption rate of KRW 4,528,260,00 [the construction cost of the instant construction project] 4,528,260,00 [the construction cost of the instant apartment 4,72% (the instant apartment 4,217,40,000,000 won) of the construction cost of the construction work (the instant construction project hereinafter “instant apartment 4,80,000,000,000 [the value-added tax of KRW 310,00,000,000,000,000 from January 24, 2018) and two parcels (F] (the construction period of KRW 310,000,000,000,00636,208]

After that, the Defendant and C changed the said contract to the effect that the completion date was extended on December 31, 2017, and the construction cost was increased to KRW 5,031,40,000 (=the instant apartment KRW 4,686,00,000).

C. (1) On August 22, 2017, between the Plaintiff and C, the Plaintiff entered into a contract with C to accept the instant subcontract (hereinafter “instant subcontract”) with the cost of construction KRW 455,00,000, and the construction period from August 28, 2017 to March 30, 2018, and the Defendant guaranteed C’s obligations under the instant subcontract.

Of the contents of the instant subcontract, the parts related to the instant case are as follows.

4. Period of construction: Amount of subcontract on March 30, 2018, the completion of which on August 28, 2017: Contract amount of 455,000,000 won/amount of 455,000,000 won/additional taxes.