The judgment below is reversed and the case is remanded to Seoul High Court.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. As to the misapprehension of legal principles as to the calculation of number of owners of superficies

A. According to Article 2 subparagraph 9 (a) of the former Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (amended by Act No. 11293, Feb. 1, 2012; hereinafter “former Act”), in cases of a residential environment improvement project or an urban environment improvement project, “owner of land, etc.” refers to the owner of land or building located in a rearrangement zone or the person with superficies thereof.

In addition, according to Article 17 of the former Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents and Article 28(1)1 of the former Enforcement Decree of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents (amended by Presidential Decree No. 24007, Jul. 31, 2012; hereinafter “former Enforcement Decree of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents”), where one parcel of land or one building belongs to several co-ownership under a housing redevelopment project, one representative of the number shall be the owner of the land, etc. (a) and where superficies is established on the land, one representative of the owner of the land and one person representing persons with superficies on the land shall be the owner of the land, etc. (b) and where one person owns a lot of land or a large number of

In light of the content and structure of the relevant laws and regulations, one person, in principle, should be calculated as the owner of a plot of land or building in a housing redevelopment project, or one person for each real estate, in cases where a co-owner is different from each other (see, e.g., Supreme Court Decision 2009Du15852, Jan. 14, 2010). In cases where a part of co-owners of a plot of land solely own a building on the ground, one person for land and a building should be calculated as the owner