A. The Plaintiff is a stock company with the purpose of rendering the building design supervision service business, and the Defendant is the owner of the A Corporation (hereinafter “instant construction”).

B. The Defendant ordered the instant construction project by dividing it into design, construction and supervision. The design for the portion of civil construction and construction as joint contractor on December 8, 2008 and the Industrial Complex Co., Ltd. (hereinafter “Designer”) was entered into a contract for each of the joint performance methods with the Plaintiff and the New Co., Ltd. (hereinafter “New Co., Ltd”) on April 10, 209, as joint contractor, and the construction was entered into a joint performance method with the Nam Young Construction Co., Ltd. and Samcheon Integrated Construction Co., Ltd. (hereinafter “City”) on May 28, 2009.

C. On September 8, 2010, in the process of performing the instant construction project, the part of the retaining wall of the reinforced soil was collapsed and the ground of Eastdong, Ridong, etc. was collapsed or damaged (hereinafter “instant accident”).

【Ground of recognition】 The fact that there has been no dispute, Gap Nos. 1 and 20 (if there are virtual numbers, including each number; hereinafter the same shall apply), Eul's written evidence No. 19, and the purport of the whole pleadings

2. Determination on the cause of the claim

A. A. A summary of the cause of the claim (1) The Plaintiff and New Copied Engineering entered into a contract with the Defendant for a change of their respective service cost to the extent of 71.79% and 28.21% on April 10, 2009, with the respective shares of 71.79% and 935,313,600 won, and the service period from May 1, 2009 to August 29, 2010, following the extension of the construction period of the instant case on November 3, 2010, upon the extension of the construction period, the Defendant entered into a contract with the Defendant for a change of the entire service cost to the extent of 1,052,010,000 won, and the service period to December 17, 2010.