A. (1) On March 28, 2012, the Plaintiff, as a credit service provider, lent KRW 30 million to D, was issued a loan certificate (Evidence 1) stating “The principal amount of KRW 36 million per annum, interest rate of KRW 39% per annum, and interest rate of KRW 36 million on March 28, 2013” from D (hereinafter “the instant loan certificate”).

(2) At the time, Defendant B, the author of D, signed and sealed the debt debt of D by signing and sealing on the joint and several guarantee column of the loan certificate of this case.

(3) Thereafter, around May 9, 2012, the Plaintiff provided a further loan of KRW 20 million to D. Meanwhile, around May 31, 2012, at the time of lending KRW 10 million to E, the Plaintiff received a joint and several guarantee as to the said loan from D.

(4) At the end of July, 2012, the Plaintiff notified Defendant B of the same fact as described in the foregoing paragraph (3) and requested Defendant B to correct the principal of the instant loan certificate. Accordingly, Defendant B corrected the Plaintiff as “60 million won” the principal of the instant loan certificate.

(5) Meanwhile, D did not pay the interest specified in the instant loan certificate to the Plaintiff after September 29, 2012.

[Ground of recognition] Unsatisfy, Gap 1-6 evidence (including virtual number), the purport of the whole pleadings

B. (1) According to the above facts, at the time of correcting the principal of the loan certificate of this case, it is reasonable to deem that Defendant B expressed its intent to jointly and severally and severally guarantee the Plaintiff’s obligation equivalent to KRW 60 million (= KRW 20 million in total), including the loan of this case and the joint and several guarantee amount (= KRW 10 million in total). Accordingly, the Plaintiff is liable to pay the agreed interest and delay damages according to the agreed rate set forth in the loan certificate of this case from September 29, 2012 to the Plaintiff.

(2) As to the above, Defendant B’s correction of the principal of the instant loan certificate was due to mistake, and thus, Defendant B did not comply with the Plaintiff’s claim.

However, the defendant.