1. The judgment of the first instance, including the Defendant (Counterclaim Plaintiff)’s counterclaim claim expanded from the trial, is as follows.

1. The court's explanation on this part of the basic facts is identical to the corresponding part of the reasoning of the judgment of the court of first instance, and thus cite it pursuant to the main sentence of Article 420 of the Civil Procedure Act.

2. Determination on the main claim

A. As to the portion of the claim for the remainder of the construction project, (1) the grounds for the court’s explanation as to the claim (a) the parties’ assertion about the invalidation, revocation, and reduction claim (b) the grounds for this part of the judgment are as stated in the relevant part of the judgment of the first instance court, and thus, this part of the judgment is accepted pursuant to the main sentence of Article 420 of the Civil Procedure Act. (2) The unfair legal act stipulated in Article 104 of the Civil Act as to whether the construction contract in this case constitutes an unfair legal act exists objectively and in return, and subjectively, such act is established when a transaction which lost balance is conducted using the old, rashness, or infinite experience of the victimized party. As such, the purpose is to regulate the breadth of acts using the old, rashness, or experience of the victimized party, which is the requirement for establishing the unfair legal act, and is sufficiently equipped with the requirement for the establishment of such legal act, and thus, it means that there is a lack of ordinary experience or experience in social life to the extent and reason for lack of knowledge.