1. The plaintiff's appeal and the main claim added by this court are all dismissed.

2. After an appeal is filed.

1. Facts of recognition;

A. On March 5, 2016, the Plaintiff was awarded a new construction contract for “high interest apartment” with respect to the 14 parcels, Jeonnam-gun, Kim Jong-gun, and the Plaintiff entered into a subcontract agreement with the Defendant on March 5, 2016 with respect to the said construction work (hereinafter “instant construction”). The date of commencement shall be March 5, 2016; the date of completion shall be Nov. 30, 2017; the contract amount shall be KRW 670,00,000; the 80% out of the contract amount as the progress payment shall be paid at the end of each month at a fair rate of 45 days after receiving a claim at the end of each month; the remainder of 20% shall be paid after completion (payment at the rate of sale and deposit); the contract deposit shall be KRW 67,00,000; and the compensation rate for delay shall be 0.3% (hereinafter “instant subcontract”).

B. On July 3, 2017, the Plaintiff sent to the Defendant a written reply demanding the performance of construction works, with content certification, and on July 18, 2017, the Plaintiff sent the Defendant a written official document dated July 14, 2017, containing a declaration of intent to terminate the contract, by content-certified mail.

C. Meanwhile, from April 30, 2016 to April 30, 2017, the Defendant claimed total of KRW 480,600,000 to the Plaintiff as follows.

Serial 16. 0. 30. 40. 40. 50. 0, 200. 10. 50, 200. 50. 50, 200. 30. 30,000 4. 65,000, 200. 6. 10. 16. 30. 60. 16. 10, 20. 16. 30. 40, 20. 16. 16. 20. 16. 30, 20. 16. 40, 20. 16. 16. 30, 20. 16. 16. 30, 20. 16. 30, 200