[2] In a case where one of the parties bears the duty of restitution upon rescission of a contract uses the subject matter, whether the duty of restitution exists (affirmative), and whether the duty of restitution equivalent to the depreciation arising from such use exists (negative with qualification)

[3] Whether the damage liability arising out of one of the both parties' debts having concurrent performance relations is concurrently performed with other debts (affirmative)

[4] Where the plaintiff extended or changed the purport of the claim in the appellate court that only the defendant appealed, whether the appellate court's acceptance of the plaintiff's claim in excess of the cited amount in the judgment of the first instance violates the principle of prohibition of disadvantageous alteration (negative)

[2] In case where one of the parties to a contract bears the duty of restitution due to the rescission of a contract, if one of the parties uses the subject matter, the benefit from the use shall be returned to the other party. Thus, even if the assignee uses it after the assignee takes over the subject matter, the transferor seeks the return of the benefit from the use to the assignee due to the cancellation of the contract of transfer, separateing from seeking the return of the benefit from the use to the assignee. Even if there were factors that may be reduced or consumed due to the use of the subject matter by the assignee, the reduction amount equivalent to the cost of the

[3] The liability for damages arising out of one of the obligations owed by both parties having a relationship of simultaneous performance is still a relationship of simultaneous performance with other obligations.

[4] In a case where the plaintiff extended or changed the purport of the claim in the appellate trial that only the defendant appealed, it shall be deemed that the incidental appeal was made to the extent unfavorable to the defendant. Thus, even if the appellate court accepted the plaintiff's claim in excess of the cited amount of the judgment of the first instance, it does not violate the principle

1. On the first ground for appeal

According to the records, prior to the filing of the lawsuit in this case, the defendant filed a lawsuit against the plaintiff seeking payment of the remainder of 25 million won and damages for delay under the transfer contract in Chuncheon District Court, 93Da1864, and the defendant dismissed only part of the damages for delay in the above court on November 26, 1993. The plaintiff appealed and appealed, but on September 9, 1994, the appellate court, also dismissed part of the damages for delay in the first instance judgment and dismissed the remaining appeal. The plaintiff filed a second appeal against the above judgment, but the Supreme Court dismissed the appeal on July 14, 1995, which became final and conclusive. However, the subject matter of the lawsuit in this case is the existence of the right to claim payment of remainder based on the transfer contract in this case, and the subject matter of the lawsuit in this case cannot be said to be identical to the subject matter of the lawsuit in this case, even if there are no identical claims based on the contract to recover the down payment and the intermediate payment.

In the same purport, the decision of the court below which rejected the defendant's argument that the lawsuit in this case goes against the res judicata of the previous suit is just, and there is no error of law in the misapprehension of legal principles as to res judicata as alleged in

2. On the second ground for appeal

According to the reasoning of the judgment below, the court below acknowledged that the original non-party was entitled to cement packaging of the non-party cement company which was transferred from the defendant, including the above non-party 3's right to receive the above cement packaging, and it is hard to find that the defendant would have received 20 million won from the non-party cement supply company instead of the defendant's waiver of the right to receive the cement packing transfer contract, and that the defendant would have received some of the balance of 45 million won under the transfer contract and returned 20 million won to the defendant's right to receive the above payment. The court below determined that the plaintiff would not have claimed that the defendant would have received 9 billion won of the above amount of the above cement transfer contract after entering into an agreement with the non-party 2 for the above reasons, and that the defendant would not have received 9 billion won of the total amount of 9 billion won of the above amount of the transferred cement transfer contract with the non-party 3's main claim that the plaintiff would have received 9 billion won of the above transfer contract.

In light of the records, the above fact-finding and decision of the court below are justified, and there is no error of law such as misconception of facts or misconception of facts due to violation of the rules of evidence, contradiction of reasons, and lack of reasons, as alleged in the ground of appeal by the defendant.

3. On the third point (the defense of the simultaneous performance)

A. The part on the fore and Pesta, fore and Pesta

If one of the parties to a contract bears the duty of restitution due to the rescission of a contract, he shall return to the other party the benefit from the use of the property if the party uses the property. Thus, even though the defendant used the part of the plaintiff after delivery of the plaintiff, it is separate from seeking the return of the benefit from the use of the property due to the cancellation of the contract of transfer of this case, and even if the above part of the plaintiff was used by the plaintiff as a result of the cancellation of the contract of transfer of this case, the amount equivalent to the reduction cost is not that of the nature of return as the duty of restitution unless it is deemed to be damaged (see Supreme Court Decision 91Da13267 delivered on August 9, 191).

Therefore, in the instant case where there is no assertion seeking the return of the profit from the use of the foreage, etc. of the instant case, the lower court recognized only the above foreage, etc. without considering the depreciation costs as claimed by the Defendant, and there is no error of law by misapprehending the legal principles on restitution.

B. Parts of brickd machines

(1) According to the reasoning of the judgment below, the court below rejected the defendant's simultaneous performance defense against the above brick machines on the ground that even if the transfer contract of this case was rescinded and the defendant already received the transfer price, the plaintiff cannot accept the plaintiff's claim until the return of the brick machines delivered by the defendant was returned pursuant to the transfer contract of this case, and that the defendant's claim cannot be accepted until the plaintiff returned the brick machines delivered by the defendant, the transfer contract of this case is not specified to the extent that the defendant can order the delivery of the brick machines, and since the non-party who is a joint assignee could not know the location after the removal, the delivery obligation was impossible, and in this case, the defendant's claim for damages due to the impossibility of performance is possible, but there is no assertion or proof

(2) In light of the records, the fact-finding and the decision of the court below that held that the above brick machines were not specified to the extent that they can be ordered to deliver them, and that their materials are not known and thus, the duty to deliver was not fulfilled is just, and there is no error in the misapprehension of legal principles as to restoration due to mistake of facts and cancellation of a contract as alleged by the defendant.

(3) On the other hand, in a preparatory document (record 681 pages) submitted to the lower court on May 12, 1997, the Defendant asserted that, if the transfer contract of this case is cancelled, the Plaintiff also returned the status at the time of bringing the brick machinery, etc. into the original state following the cancellation of the contract, or that he would reimburse it.

The defendant's above assertion is likely to be included in the purport of seeking compensation for damage caused by the failure to perform the duty of delivery of the above brick machines. Meanwhile, since the damages liability arising from the failure to perform one of the obligations of both parties related to simultaneous performance is still in the relationship of simultaneous performance with other obligations (see Supreme Court Decision 96Da4067, 40684 delivered on April 25, 1997). The court below's determination should be made by clarifying in the defendant's defense of simultaneous performance whether the above duty of delivery of the brick machines includes the purport of seeking compensation for damages if the duty of delivery of the above brick machines is impossible, and it should be deliberated and determined after exercising the right of explanation, but the rejection of the defendant's defense of simultaneous performance with respect to the above brick machines by the defendant without any assertion or proof, which affected the conclusion of judgment due to failure to exercise the right of explanation or omission of judgment. The defendant's ground of appeal pointing this out has merit.

4. On the fourth ground for appeal

In a case where the plaintiff filed an appeal only by the defendant extended or modified the purport of the claim, it shall be deemed that the appellate court filed an incidental appeal to the extent unfavorable to the defendant. Thus, even if the appellate court accepted the plaintiff's claim in excess of the cited amount of the judgment of the first instance, it does not violate the principle of prohibition of disadvantageous alteration (see, e.g., Supreme Court Decisions 91Da21688, Sept. 24, 1991; 91Da43015, Dec. 8, 1992).

Therefore, the judgment of the court below is not erroneous in the misapprehension of legal principles as to incidental appeal as alleged by the defendant.

5. Therefore, the part of the lower judgment against the Defendant is reversed, and that part of the case is remanded to the lower court for further proceedings consistent with this Opinion. It is so decided as per Disposition by the assent of all participating Justices on the bench.

Justices Lee Im-soo (Presiding Justice)