(b) Where a creditor returns the successful bid price paid to a successful bidder as the registration of transfer of ownership based on the successful bid is cancelled due to the invalidation of cause, the validity of repayment due to such dividend;

B. If the successful bidder is unable to acquire ownership because registration of transfer of ownership in the name of the successful bidder based on the successful bid is cancelled due to the invalidation of the cause, and the debtor and the owner are insolvent, and the creditor who received the successful bid price returned the successful bid price to the successful bidder, this is due to the duty to restore the successful bid price, and thus, the creditor should be deemed to have not paid the original claim because the repayment of the original claim due to the distribution becomes null and void, not by newly acquiring the right to return unjust enrichment against the debtor

Even if a joint and several surety contract and a water guarantee contract were concluded for the same bond security, since a joint and several surety contract and a water guarantee contract cannot be deemed as a separate contract and have legal characteristics, it cannot be seen as a separate contract, so even if the water guarantee contract was rescinded, unless otherwise stipulated (Supreme Court Decision 84Meu1655 delivered on December 26, 1984). According to the records, it is not proved that the plaintiff exempted the defendants from the joint and several surety obligation, and there is no evidence that the plaintiff exempted the defendants from the joint and several surety obligation, as part of the amount of the joint and several surety obligation guaranteed by the defendants, and only the fact that the plaintiff was paid 80 million won in amount to the security value of the secured real estate, and the withdrawal of the auction of the secured real estate owned by the defendants and the cancellation of the registration of mortgage creation, it is justifiable in the court below's decision that the exemption of the obligation of this case cannot be deemed as a joint and several surety obligation. There is no error in violation

The grounds of appeal No. 2 are examined.

The court below duly acknowledged that the plaintiff received 6,00,000 won of the successful bid price and appropriated the loan claim of this case on the ground that the registration of transfer of ownership based on the successful bid in the name of non-party 1, the successful bidder, was cancelled on the ground that the cause becomes null and void on the ground that the registration of transfer of ownership based on the successful bid in the name of the non-party 1, the debtor and the non-party 2, who was the debtor and the owner of the above non-party 1, was insolvent, and thus the plaintiff received dividends and won the lawsuit claiming the return of the successful bid price against the plaintiff, and the plaintiff returned the successful bid price to the above non-party 1. The amount equivalent to 6,00,000,000 won out of the loan claim of this case was extinguished upon receiving the successful bid price and then appropriated for the repayment of the above debt, and thus, the extinctive prescription period for the loan debt of this case was no longer effective for the period of 10 years elapsed since the plaintiff acquired the claim for return of unjust enrichment against the defendant's joint guarantor.

However, the plaintiff's return of the successful bidder's auction price to the successful bidder because the registration of transfer of ownership in the name of successful bidder was cancelled due to the invalidation of cause, and the successful bidder is unable to acquire ownership, and the debtor and the owner are insolvent, is attributable to the duty to restore the successful bidder according to the rescission of contract. Accordingly, the plaintiff's return of the successful bidder's auction price is not a new acquisition of the claim for return of unjust enrichment, but the repayment of the loan claim due to dividend becomes null and void, so the original claim for the loan remains unpaid. Thus, the decision of the court below that held a claim for extinctive prescription based on the premise that the plaintiff's claim of this case is not a loan claim, but a claim for return of unjust enrichment, which is a claim for return of unjust enrichment, erred by misapprehending the legal nature of the return of the successful bidder'

Therefore, the part of the judgment of the court below against the defendants shall be reversed and remanded to the Seoul High Court. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Park Jong-dong (Presiding Justice)