According to the reasoning of the judgment below, the court below acknowledged that the non-party purchased the real estate on January 19, 1968 between the non-party and the plaintiff, and that the non-party purchased the real estate from the defendants on October 19, 1967, the previous transfer of ownership of the real estate. Since the non-party was unable to implement the transfer of ownership of the real estate, the plaintiff declared his intention to cancel the above sale to the plaintiff, and the contract cancellation of the contract was effective. The non-party has a duty to compensate the damages suffered by the plaintiff due to the non-party's failure to perform the contract because the non-party had the right to claim compensation for damages equivalent to the amount of damages that the non-party would be paid to the plaintiff for the same reason, and the non-party is not entitled to exercise this claim and the non-party has no intent to perform the liability for compensation due to the rescission of the contract. Thus, the court below held that the plaintiff can exercise the right of compensation for damages against the non-party by subrogation against the non-party for the above claim.

However, in order for a creditor to exercise his/her right to preserve his/her own claim, he/she is entitled to exercise the right on behalf of the creditor against the third debtor. In addition, when the creditor's right to subrogation is a monetary claim (including damage claim), the creditor can not exercise his/her right only with the absence of an intent to perform his/her obligation, and can exercise it in cases where it is necessary to prevent reduction in general property due to the debtor's insolvent. In this case, the court below should have decided that the defendant's right to claim damages against the third debtor of the non-party, who is the non-party, for the same reasons as the plaintiff's claim against the non-party, at least on the ground that the non-party had a right to claim damages equivalent to the amount of damages which the non-party would have paid to the plaintiff without any final determination as to the non-party's claim, and it should have been resolved that the plaintiff's right to claim damages should not be exercised in subrogation of the non-party's principal contract with the plaintiff and the defendant's right to claim damages.

Therefore, by the assent of all participating judges, the original judgment is reversed, and the case is remanded to the Daegu High Court. It is so decided as per Disposition.

Supreme Court Judge Ma-dong (Presiding Judge) Ma-dong (Presiding Judge)