1. All of the plaintiffs' claims are dismissed.

2. The costs of lawsuit are assessed against the plaintiffs.

1. The following facts may be found either in dispute between the parties or in full view of the overall purport of the pleadings in Gap evidence Nos. 1, 2, 4, 6, 8, 10 to 13 (including all of the serial numbers, hereinafter the same shall apply), Eul evidence Nos. 3 through 12, 15 to 18, witness D's partial testimony, and witness E's testimony:

Before the partition, the petitioner-gu Seoul Special Metropolitan City was jointly owned 45,824m24m2 (hereinafter referred to as “the forest before subdivision,” hereinafter referred to as “Gri”) with the relevant lot number, and the Plaintiff A shared 10964/45824 shares, and the Plaintiff B shared 34860/45824 shares.

B. On March 27, 2015, the Defendant, the owner of H land adjacent to the forest land before subdivision, purchased the part of 1,322 square meters adjacent to H land among the forest land before subdivision from the Plaintiffs, and thereafter, on May 12, 2016, the forest land before subdivision was divided into F forest land 4,860 square meters, 1,860 square meters, 20,938 square meters, and J forest 20,026 square meters, respectively. On June 8, 2016, the part of the Defendant purchase from J land (hereinafter “Plaintiffs”) was divided into 1,322 square meters from J forest land (hereinafter “Defendant purchase land”). The land of the Plaintiffs and the Defendant purchased the land were divided into each of the instant land.

C. Meanwhile, at the time of the Defendant’s purchase of the part of the Defendant’s purchased land among the forest land before subdivision on March 27, 2015, the part of the land adjacent to the boundary between the Plaintiffs’ land and the Defendant’s land was constituted a slope. Based on the boundary, the Plaintiffs’ land was located on the upper part and the lower part of the land purchased by the Defendant.

On June 2015, in order to build a “L” factory on the ground of forests and fields, other than the land purchased by the Defendant, on or around 77.6 meters of the total length of each of the lands of this case, the Plaintiffs are vertical reinforcements, the height of which is about 4.9 meters on the land of the Plaintiffs on the part of 50 meters of length of the land of this case, excluding the land purchased by the Defendant.