1. The defendant (Counterclaim plaintiff)'s appeal is dismissed.

2. The costs of appeal are assessed against the Defendant (Counterclaim Plaintiff) in total.

1. The Plaintiff was issued and delivered a loan certificate from the Defendant and C on March 15, 2010 (hereinafter “the loan certificate of this case”) around 2010 through 2011. The content was that ① the Plaintiff lent KRW 64.6 million to the Defendant, but the Defendant repaid to the Plaintiff KRW 25 million up to December 31, 201, up to January 31, 201, the amount of KRW 25 million up to January 31, 201, and the remainder KRW 14.6 million up to June 30, 2012. ② C was jointly and severally guaranteed by the Defendant’s debt based on the loan certificate of this case.

[Ground of recognition] Facts without dispute, Gap evidence No. 1, Eul evidence No. 2, the purport of the whole pleadings

2. Determination on the main claim

A. According to the above facts, barring any special circumstance, the Defendant is obligated to pay the Plaintiff the amount of KRW 14.6 million calculated by deducting the amount of KRW 50 million paid by the Plaintiff himself/herself from “the amount of KRW 64.6 million, a loan on the loan certificate of this case, which is a joint and several surety,” and delay damages therefor (=64.6 million).

B. Determination 1 on the defense, etc. 1) As long as C, a joint guarantor, repaid to the Plaintiff KRW 31 million on or around March 2010, the Defendant himself, as well as the Defendant, on or before the repayment of KRW 50 million to the Plaintiff, the Defendant paid the Plaintiff KRW 31 million, the Defendant’s obligation to return the loan amount (= KRW 50 million) upon the repayment of KRW 31 million in the end, the Defendant asserts that the full amount of the debt based on the loan certificate of this case has already been paid (or by mistake, the amount exceeds KRW 16.4 million (= KRW 81 million-64 million). Thus, the Plaintiff’s obligation to return the above KRW 16.4 million to the Defendant as unjust enrichment is also included in the purport that the Plaintiff is also obligated to return the loan amount to the Defendant.

[2] In full view of the overall purport of the pleadings in the statement No. 7 and No. 3 (including paper numbers), the Defendant’s spouse was transferred KRW 30 million from the account in the name of E on March 18, 2010 to the account in the name of E on March 18, 2010, and KRW 1 million from March 30, 2010 to the account in the Plaintiff’s name.