All appeals are dismissed.

The costs of appeal are assessed against the Defendants.

The grounds of appeal are examined.

1. As to the ground of appeal No. 1, the lower court rejected the Defendants’ assertion that there was no right to claim a return of unjust enrichment equivalent to the rent on the instant site since the former owner of the instant site consented to the gratuitous use of the site or renounced the right to claim a return of unjust enrichment equivalent to the rent, and the Plaintiff also acquired the ownership under the well-known and acceptable state.

Examining the record in light of the relevant legal principles, the above determination by the court below is just, and contrary to the allegations in the grounds of appeal, there were no errors of acknowledging facts contrary to logical and empirical rules or of misapprehending the legal principles on unjust enrichment or claim for land use.

2. As to the grounds of appeal Nos. 2 and 3

(a) In case where the land and a building were owned by the same person, and the owner is changed due to sale or other causes, the owner of the building shall acquire a legal superficies under customary law against the site owner, unless otherwise stipulated that the building be demolished in particular; and

(See Supreme Court Decision 94Da41072 delivered on December 22, 1994, etc.). However, a transferee of a building with statutory superficies under customary law cannot be said to have acquired statutory superficies only with the fact that he/she acquired the ownership of the building unless it is registered as to statutory superficies. Therefore, he/she cannot claim the superficies against the owner of the building site.

(See Supreme Court Decision 94Da39925 delivered on April 11, 1995, etc.) In addition, the assignee of a building with statutory superficies may refuse to remove the building owned by the site owner or to request the delivery of the site in a position to acquire the legal superficies in the future.

Even if the gain accrued from occupying or using the land, the owner of the land is obligated to return the gain as unjust gains.

(See Supreme Court Decision 96Da34665 delivered on December 26, 1997, etc.). B.

The judgment below

According to the reasons and records, this case is examined.