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

The grounds of appeal are examined.

1. The facts established by the lower court by citing the first instance judgment are as follows. A.

On August 27, 2007, the Defendant entered into a contract for construction works (hereinafter “instant construction contract”) with Daedong-NC Co., Ltd. (hereinafter “JC”) by setting the contract amount of 33,740,000,000 won for the construction works of the five sections (hereinafter “instant construction works”) for the apartment in Daegu-gu with the joint contractors consisting of Taedong-NC Co., Ltd. and the Japanese comprehensive construction works (hereinafter “TJ”).

B. On the same day, the Plaintiff entered into a performance guarantee contract with the Defendant, the guaranteed creditor, the guaranteed amount of KRW 16,870,000,000, and the guarantee period from August 27, 2007 to November 30, 2009 (hereinafter “instant performance guarantee contract”) and issued the performance bond.

C. On January 23, 2009, the instant construction was suspended following the application for rehabilitation procedures by Dan-dong, and the completion of the construction of the instant construction by succession to the remaining construction, but continued to be delayed. On August 17, 2009, the Defendant filed a claim against the Plaintiff for the performance of the guaranteed obligation. At the time, the construction period was 263 days in preparation for the progress rate at 44.07%, and the construction period was 263 days.

On October 6, 2009, the Plaintiff entered into a guarantee construction consignment agreement with the first type of construction business chain and continued the instant construction upon obtaining approval from the Defendant. Upon the Plaintiff’s application for extension of the construction period, the Defendant extended the construction period to 30 days on November 30, 2009 (construction, machinery) and December 20, 209 (civil engineering).

E. On May 7, 2010, the Plaintiff completed each civil engineering work on May 13, 2010, and completed the construction work to the Defendant.