1. The plaintiff's appeal is dismissed.

2. Upon the plaintiff's preliminary claim added at the trial, the defendant shall be the plaintiff.

1. The parties' assertion

A. On January 17, 2018, the Plaintiff, around the Plaintiff’s assertion, lent KRW 30 million to the Defendant, and the Defendant, in preliminary order, agreed to return the principal by receiving KRW 30 million from the Plaintiff, bitco-in investment.

Therefore, the defendant is obligated to return 30 million won to the plaintiff.

B. Although the defendant alleged that he received KRW 30 million from the plaintiff, the above KRW 30 million is not a loan but an investment in bitco. Thus, the defendant has no obligation to repay it.

2. The plaintiff's assertion that he lent money between the parties to the judgment as to the primary claim, even though there is no dispute as to the fact that he received money between the parties to the judgment as to the primary claim has the burden of proving that he lent money

(2) According to the reasoning of the judgment below, the Plaintiff’s transfer of KRW 30 million to the account held in the name of the Defendant on January 17, 2018 (see, e.g., Supreme Court Decision 2017Da37324, Jan. 24, 2018) to the account held in the name of the Defendant on January 17, 2018, and the Plaintiff and the Defendant’s transfer of KRW 30 million to the account held in the name of the Defendant on February 20, 2018, although the loan certificate (Evidence 2) was written on February 20, 2018, it is recognized that the Plaintiff’s transfer of KRW 30 million to the Defendant on February 20, 2018 was written, but the entire purport of the pleadings was comprehensively considered on January 17, 2018, namely, the Defendant recommended the Defendant to purchase KRW 30 million from the Plaintiff on January 17, 2018 to the Defendant’s transfer of text messages to KRW 300 million.