The plaintiff is an executor who promoted the construction project of the "unisodong apartment B block" in the middle-gu Seoul Metropolitan Government Seocho-dong 170, and the defendant is a contractor who entered into a construction contract with the plaintiff to build an apartment (hereinafter "the building of this case") in the project site and entered into a construction contract with the plaintiff (hereinafter "the construction of this case").

On July 21, 2006, the Plaintiff determined the contract construction cost for the instant construction project as KRW 97,912,797,00 (excluding value-added tax) with the Defendant, and the contract construction cost as KRW 4,100,000 per square meter (excluding value-added tax), and entered into an agreement on the contract for construction project (hereinafter “instant contract agreement”) with the Plaintiff and the Defendant to determine the apartment sale price in consideration of the market situation at the time of the parcelling-out. The Plaintiff’s and the Defendant agreed on the apartment sale price in consideration of the apartment and the sales price as KRW 13,50,000 per square meter, KRW 30,000 per square meter, KRW 30,000 per square meter, KRW 13,755,00,000 per square meter, and KRW 14,500,000 per square meter.

On October 19, 2007, the Plaintiff entered into a contract with the Defendant to set the construction amount of KRW 120,477,00,000 (including value-added tax) and the construction period of KRW 39 months from the commencement date of works (from October 2007 to December 2010), respectively (hereinafter “instant contract”). The terms and conditions of the construction contract included in the said contract are as follows:

Article 3 (Classification of Business Activities) The project shall be the project implementer and the defendant shall be the execution agent and sales agent of the project.

1. Scope of the Plaintiff’s business: Provision of a business site (including entry roads and donated sites).

(7) Expenses incurred in the sale of commercial buildings (including fees for sales on behalf of the shopping district and advertising expenses)

3. Business scope of the defendant, construction of apartment and commercial buildings, and