1. The plaintiff's claim is dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. According to the evidence evidence Nos. 1, 2, and 3 as to the argument on the cause of the claim, the plaintiff lent KRW 50 million to the non-party C Co., Ltd. (hereinafter "non-party Co., Ltd.") on March 30, 2006 at the due date for repayment on May 30, 2006 (hereinafter "the loan of this case"), and the defendant may recognize the fact that the non-party Co., Ltd. provided joint and several surety (hereinafter "joint and several surety of this case").

According to the above facts of recognition, the defendant is jointly and severally liable to pay to the plaintiff 50 million won and damages for delay calculated at the rate of 15% per annum from January 20, 2016 to the day of full payment, as claimed by the plaintiff, as the delivery day of a copy of the complaint in this case, to the day of full payment, as the plaintiff seeks.

2. Determination of the parties' defense

A. The Defendant’s defense of the extinctive prescription against the Defendant’s commercial claim includes not only the basic commercial activities falling under any of the subparagraphs of Article 46 of the Commercial Act, but also ancillary commercial activities performed by the merchants for their business (see Supreme Court Decision 98Da23195, May 12, 2000). In addition, the Defendant asserted that the extinctive prescription against the Plaintiff was expired on May 31, 201 as a commercial debt, and that the Defendant’s obligation to the Plaintiff was extinguished after the lapse of the extinctive prescription period for commercial activities. 2) In addition, the Defendant asserted that the guaranteed liability of this case was extinguished due to the subsidiary nature of the guaranteed liability. In addition, the act performed by the merchants is presumed to be an act performed by the merchants as a commercial activity even if it did not engage in commercial activities, but also an act performed by the merchants for the purpose of commercial activities, as long as there is no evidence supporting that the act was performed by the merchants.