1. The defendant (Counterclaim plaintiff)'s appeal is dismissed.

2. The defendant-Counterclaim plaintiff's counterclaim brought at the trial.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. The following facts do not conflict between the parties, or may be acknowledged by taking into account each entry of Gap 1-3 and 6 (where the branch numbers are not specified, including all the numbers of the pertinent documentary evidence; hereinafter the same shall apply), Gap 4 and 5, the result of field inspection conducted by the first instance court, and the whole purport of the pleadings:

On September 9, 2013, the Plaintiff entered into a contract with the Defendant on September 9, 2013, the Plaintiff: (a) set up a construction project that newly constructs a yellow civil engineering structure housing of the second floor (hereinafter “instant housing”); (b) three months from the commencement date of the construction period; and (c) the construction cost of KRW 180,000,000 on the ground (hereinafter “instant construction project”).

(hereinafter “instant contract”). (b)

The Defendant started the instant construction work on April 14, 2014 under an agreement with the Plaintiff, and the Plaintiff paid the Defendant KRW 10,000,000,000 in total, with the down payment and the progress payment of the instant construction work, on September 9, 2013, as the down payment and the progress payment of the instant construction work, on April 16, 2014, and KRW 55,00,000,000 on July 31, 2014.

C. The Defendant did not complete the instant construction work by July 14, 2014, which was three months after the commencement date of the construction work, and the construction work was suspended without completing the instant construction work even before August 15, 2014, which was extended by agreement with the Plaintiff.

On September 25, 2014, the Plaintiff filed the instant principal suit with the purport to seek the payment of the remainder of the construction cost, excluding the construction cost according to the fixed rate and the fixed-term and prepaid construction cost, on the grounds of the Defendant’s delay of performance. The duplicate of the principal complaint was served on October 6, 2014.

2. Determination on the main claim

A. The plaintiff 1's assertion of the parties did not complete the construction of this case with the lapse of the extended construction period after suspending the construction of this case. Thus, the plaintiff's delay on the ground of the defendant's delay of performance.