Mobility and Spatial Stratification : The Politics of Underground Space through the Development of Seoul’s Subway System

The emergence of diverse architectural techniques has facilitated vertical urbanization, wherein the spatial hierarchy of upper and lower levels, in conjunction with societal class structures, has significantly influenced urban space reorganization. However, this vertical urbanism has been limited in its ability to transcend existing dichotomies, such as horizontal-vertical and upper-lower relationships. Moreover, it has not fully illuminated the logic underlying the interconnectedness of ground, surface, and underground spaces. This study examines the dynamics of cities by integrating urban verticality with mobility as a fundamental operational principle. The research demonstrates how the emergence of mobility has catalyzed a process of spatial stratification, whereby cities have evolved into configurations that accommodate movement both below and above ground to meet human mobility requirements. To achieve this objective, the case analysis focuses on various opinions for developing a spatially stratified subway system and the mobility patterns facilitated by such stratified space. Specifically, this study examines Seoul's subway development proposals from the 1920s through the diversification and concretization of transit lines in the 1960s and early 1970s. Through an exploration of urban actors and their spatial and temporal contexts, this research aims to identify how transport infrastructure, as stratified space, constitutes mobility within the city.