The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. For the purpose of rescission or agreement of a contract, the requirement is that the opposite expression of intent, which is to terminate the validity of a contract, is consistent, as in the case of general cases of the formation of a contract, is to be agreed upon. To establish such an agreement, the contents of intent expressed by both parties must objectively coincide with each other. The cancellation or agreement may be impliedly made. However, if a contract is to be rescinded or agreed upon implicitly, it should be agreed that both parties would not realize the contract due to the lack or renunciation of their intent to realize the contract (see, e.g., Supreme Court Decisions 98Da17602, Aug. 21, 1998; 200Da5336, 5343, Jan. 24, 2003; 200Da5336, 5343, Jan. 24, 2003).

(2) According to the reasoning of the lower judgment and the record, the Plaintiff concluded a standard purchase contract (hereinafter “instant contract”) with the Defendant on October 25, 2007, regarding the part of the exhibition facilities in the B district subcontracted by GS Construction Co., Ltd. (hereinafter “GS Construction”), among the parts of the exhibition facilities in the B district subcontracted by the Plaintiff from GS Construction Co., Ltd. (hereinafter “instant project”), the Plaintiff paid KRW 3,922,490,000 for the cost of the exhibition facilities in the field, including the Sea Day Experience Center, Lotland, the Dazland, the Disaster Station, the Central Hall, and the cost of the production and installation of the goods, and re-subcontracted the production and installation of the detailed drawings on August 31, 2009 (hereinafter “instant contract”).