B. Whether the legal superficies under customary law can claim the above superficies against the third party purchaser of the target land without registration (affirmative)

B. Since legal superficies under customary law are the acquisition of real rights to real properties under customary law, the acquisition of superficies takes effect without requiring registration, and under customary law superficies can be claimed against the landowner at the time of acquisition of them by the validity as real rights or against a third party who acquired ownership from them without registration.

The plaintiff's appeal against the defendant 2 and the remaining appeal against the defendant 1 are dismissed, respectively.

The costs of appeal by the dismissal of an appeal shall be borne by the plaintiff.

Point 1 (The primary part of the claim against the defendant)

Unless there is a condition that the owner of the land or a building belongs to the same owner, but the owner of the building or the land becomes different from each other due to sale and purchase of the building or any other cause, the owner of the building will acquire legal superficies for the owner of the building (see Supreme Court Decision 79Da2000, Jul. 8, 1980). This superficies is not a acquisition of a real right due to a juristic act, but is a acquisition of a real right to real estate under customary law, so it takes effect without requiring registration. Under customary superficies, the owner of the land or a third party who acquired the ownership from the owner of the land at the time of acquisition of the superficies as a real right or a third party who acquired the ownership from the owner of the building (see Supreme Court Decision 70Da2576, Jan. 26, 1971). In light of the reasoning of the judgment below, the court below determined that there is no error in the misapprehension of legal principles as to the above land owner of the building or the above building without the above land owner's legal superficies.

Point 2 (Preliminary Claim against Defendant 1)

According to the reasoning of the judgment below, the rent of this case was calculated on the premise that the rent of this case was KRW 77,400 per annum (6,450 per annum) for 1306 square meters in Gyeonggi ( Address 1 omitted) but there is no evidence to prove that the rent of the above site was KRW 77,400 per annum after July 29, 1982 according to the records (as the appraisal report of the non-party, the appraisal report cited by the court below was followed by the appraisal report of the non-party, and there is no evidence to support that the rent of this case was KRW 77,400 per annum (as the appraisal report of the non-party, 172 square meters in 172 square meters in 172 square meters in 172 square meters in 1982). Thus, the court below's calculation of the rent of this case was in violation of the rules of evidence, and it did not err in the misapprehension of the judgment of the court below, but did not err in the misapprehension of justice and equity.

Therefore, since the Plaintiff’s conjunctive claim against Defendant 1 is with merit, the part of the lower judgment’s conjunctive claim against Defendant 1 is reversed, and that part of the lower judgment’s conjunctive claim against Defendant 1 is remanded to Suwon District Court Panel Division, which is the lower court. The appeal against Defendant 2 and the remainder of appeal against Defendant 1 are without merit. Accordingly, each of the appeals against Defendant 1 is dismissed, and the costs of the appeal against the dismissed part are assessed against the Plaintiff, who is the losing party, as per Disposition

Justices Kim Young-ju (Presiding Justice)