The Conceptual Origins of the Rosario Plan for Seoul in 1980 : Finding the Logical Backgrounds to the Transit-Oriented Metropolis Plan

1. Linear City and Its Successors

Arturo Soria y Mata in Spain proposed the “Linear City” concept in 1882, emphasizing improved access via trains (See <Figure 1>). In this suburban city model, residential complexes, comprising houses and related facilities, are organized along a series of railroad networks, — originally horsedrawn and later by streetcars in 1909 (Hall, 2002).

Figure 1.

The linear city by Soria y Mata in 1882Source: Palacio (1969)

Although Soria’s proposal has been criticized for being less than an urban scale, it has been utilized in urban construction models worldwide (Doxiadis, 1967; Hall, 2002). The idea of the linear city was primarily applied as a decentralized urban spatial structure, aligning well with decentralized political ideologies. The concept was introduced globally by the Association Internationale des Cités Linéaires, founded in 1928 by French planner Georges Benoit-Levy (Hall, 2002). In 1930, Nikolay A. Milyutin in the Soviet Union proposed a deurbanistic linear city for Sotsgorod (Socialist City), and his plan for Stalingrad was based on linear expansion with parallel city functions (Doxiadis, 1967).

On the other hand, the concept of a linear city was also adapted to high-density urban areas in the capitalist countries. Aiming to create a city based on a modernistic vision, Le Corbusier incorporated the idea of the linear city in his vision for La Ville Radieuse (The Radiant City) (Hall, 2002; Cho, 2014). In the 1950s, the Brazilian government constructed Brasília, a new administrative capital that adhered closely to Lúcio Costa’s interpretation of the linear city concept (Hall, 2002), and the concept was applied in the Hook New Town in the United Kingdom (Jung and Hong, 2024).

In 1960, Kenzo Tange in Japan applied linear planning principles in his plan for Tokyo (Tange, 1961). In the late 1960s, Doxiadis utilized the linear city concept while designing the master plan for Islamabad, the new capital of Pakistan. In this plan, he separated different functions and introduced a concept where superblocks are continuously expanded (See <Figure 2>).

Figure 2.

Linear city concept for Islamabad by DoxiadisSource: Doxiadis (1967)

Many countries have continued to utilize the concept of a linear city in their urban planning and development efforts. In a recent study, Jung and Hong (2024) discovered that the concept of the linear city has been included in the district plans of many new towns in South Korea since the 1990s. A recent notable example is Saudi Arabia, which announced plans to build a linear city called ‘The Line,’ extending up to 100 miles. Inhabitants of this city will use autonomous mobility and ultra-high-speed transit for transportation (Avery, 2021).

Doxiadis (1967) demonstrated that a linear city could undergo various transformations and showed that its form might vary depending on the topographical conditions or the configuration of the existing city center. A linear city is not only a modification of the methods that connect straight line or curvilinear, but also other types of figures, a representative example as a circular shape connecting the ends of lines, a ring-shaped.

Among the cities constructed with a circularspatial structure, the representative ones are Sejong City, an administrative complex city in South Korea. In an international competition for designing a proposal for the city, five designs were selected in the design competition in 2005. The city spatial structure of the new administrative capital was decided based on two plans having a ring-shaped spatial structure (See (a) in <Figure 3>): Andres Perea Ortega (2005), The City of Thousand Cities (See (b) in <Figure 3>) and Jean Pierre During’s The Orbital City. Interestingly, both of these proposals were put forward by Spanish architects.

Figure 3.

Ring-shaped spatial structure of Sejong City in South KoreaSource: (a) NAACC (2017); (b) Ortega (2005)

The two proposals featured a decentralized spatial structure and received strong support from David Harvey, the renowned Marxist economic geographer who served as the co-chair of the competition committee at the time (Ohn, 2016: p.164-166).²⁾ It is uncertain to discuss whether Sejong City’s spatial structure is influenced by political perspectives. Around 30 years prior to the Sejong City’s ring-shaped structure proposal, Kahng (1977) suggested a plan to expand the existing downtown of Seoul in a circular layout. However, this idea remains not well unknown. According to his disciple, Kun-ho Lee, Professor Kahng described his Rosario Plan as a linear city with connected ends (Sung and Choi, 2017).³⁾ Like the previous example, the transition from linear cities to circular spatial structures should be recognized as a significant topic in the history of urban planning.

2. Christopher Alexander’s Alternative to Modernistic Urban Planning

Christopher Alexander, a prominent figure in critiquing modernism in architecture, urban planning, and design while proposing alternatives, is best known for his 1977 book, “A Pattern Language.” In this work, he identified the characteristics of spaces that existed prior to modernism and offered various design methods for creating meaningful ‘places.’ Alexander’s proposals have since been adopted by many planners (Bhatt, 2010).

His ideas have sparked focused discussions around urban design that many experts are currently engaging in and are widely recognized. However, Alexander’s 1965 proposal for urban structure remains relatively obscure, and subsequent designs based on his concepts have yet to be validated. Alexander (1965) published an article in the Architectural Forum titled “A City is Not a Tree,” in which he argued that the “artificial cities” created by urban planners lack the organic structure inherent in “natural cities.” Alexander illustrated his argument with a diagram, shown in <Figure 4>, contrasting the rigid and hierarchical structure of planners' designs, which he referred to as a tree structure, with the more flexible and interconnected relationships found in a semi-lattice structure. He contended that artificial cities fit the former category, while natural cities exemplify the latter. The semi-lattice structure is said to generate a more diverse array of urban forms compared to the tree structure. Alexander criticized the rigidity of urban designs such as Costa’s Brasília and Tange’s plan for Tokyo, which are typical examples of linear planning (Alexander, 1965: p.58-61).

Figure 4.

Comparison of semi-lattice structure and tree structureSource: Alexander (1965)

3. Transit-Oriented Development (TOD) and Metropolis (TOM)

TOD is a planning principle introduced by Calthorpe (1993) as an alternative to address urban challenges caused by excessive road traffic and urban sprawl in the United States. This concept is centered around transit hubs and a network of public transportation. Calthorpe advocated for urban forms characterized by high density, mixed land use, and walkable designs, aiming to reduce dependence on automobiles while enhancing the vitality of neighborhoods. His approach encompasses not only the idea of “pedestrian pockets” but also considers the regional scale of development. Despite being primarily small-scale and focused on district development around transit, discussions have emerged emphasizing the need for a metropolitan and/or regional development strategy. This involves transitioning to transit-oriented corridor and transit metropolis (e.g., Cervero, 1998; Cervero and Sullivan, 2011; Belzer, 2011).

Calthorpe (1993) introduced the concept of TOD and its main components, while Cervero and his collaborators further developed the planning elements. Initially, Cervero and Kockelman (1997) refined these into the “3Ds” (density, diversity, design), focusing on high-density mixed land use and walkable urban design. Later, Cervero and Murakami (2009) and Ewing and Cervero (2010) added “2Ds” (distance to transit and destination accessibility), highlighting the importance of public transportation accessibility in TOD implementation.

Sung and Choi (2017) introduced the term Transit-Oriented Metropolis (TOM) to highlight efforts in developing a metropolitan-area railway network amid urban expansion.⁴⁾ This concept, which originated in England, developed at the metropolitan level through various plans, including Copenhagen’s 1947 Finger Plan, Stockholm’s 1952 Plan, Paris’s 1965 Plan, and Tokyo’s 1923 Plan (Cervero, 1995; Hall, 2002; Watanabe, 1977). Recently, Kahng’s Rosario plan has been recognized as a crucial connection between metropolitan-level planning focused on transit and new towns in the early to mid-20th century and the contemporary discussions surrounding TOD (Sung and Choi, 2017).

1. Tokyo Plan in 1960

Kahng participated in Kenzo Tange’s 1960 Tokyo plan and began extensive research on cities in the late 1950s (Lee, 2009). The plan was completed by Tange along with his five young disciples and architects from the University of Tokyo: Koji Kamiya, Arata Isozaki, Sadao Watanabe, Noriaki (Kisho) Kurokawa, and Heiki Koh (Byong-Kee Kahng) (Lin, 2010). At that time, Tange’s lab focused on integrating all aspects of city design, with Kahng presumed to be responsible for transportation planning.⁵⁾

The Tokyo Plan 1960 identified issues with Tokyo’s existing centripetal spatial structure and proposed a new linear development (see <Figure 5>). To address the limitations of the previous radial city model, it recommended an open linear urban structure achieved through the organic integration of cities, transportation, and architecture (Tange, 1961). For Kahng, the Tokyo Plan 1960 was a pivotal moment in his urban research, instilling the concept of the Linear City, a modernist design by Soria y Mata that would influence the spatial structure of many urban plans he worked on after the 1960s.

Figure 5.

Tokyo Plan 1960 by Kenzo TangeSource: Archeyes (2022)

2. Seoul Spatial Structure Proposal in 1977

In the 1970s and 1980s, Seoul was seeking a decentralized policy for two main reasons. First, the city faced planning challenges due to its mono-nuclear structure, which concentrated commercial, office, and educational facilities in the center. Most bus routes passed through this central area, and rapid automobile growth, fueled by economic development, was expected. However, the possibilities for road expansion in urban areas were limited (Kim, 1977).

The second reason was related to military defense. The excessive population concentration north of the Han River was seen as a significant military vulnerability (Son, 2005). During the Korean War in 1950, North Korea captured Seoul within three days, leading to numerous casualties, injuries, and abductions among South Koreans who could not evacuate. This situation was deemed undesirable for South Korea, which was positioned as a political outpost during the Cold War. Throughout the 1970s, the Korean government continued efforts to decentralize functions in Seoul (Choi et al., 2019).

In the mid-1970s, Seoul Mayor Ja-chun Koo adopted Professor Hyung-man Kim’s proposal for a three-nuclear city to disperse the mono-centric central business district (CBD) of Seoul, South Korea (Kim, 1977; Son, 2003). To formalize and implement Kim’s suggestion, the mayor organized idea competitions (Son, 2003). During this competition, Kahng was invited to submit a proposal (Lee, 2009). He suggested a polynuclear structure characterized by a “gathering and distribution shape” (集散形) (see <Figure 6>).

Figure 6.

Ring-shaped spatial structure proposal for Seoul by Kahng in 1977Source: Kahng (1977)

Kahng proposed a circular structure near the city center, combined with a radial system for the city’s periphery. He emphasized that the subway network would be crucial in restructuring the urban layout and argued that it should support a ring shape, which he termed the “action ring” (Kahng, 1977). In this plan, Kahng first introduced a ring-shaped transport network and demonstrated how the linear city concept, aimed at a distributed spatial structure, could be transformed into a ring form.

3. New Administrative Capital Plan for South Korea in 1979

Since the late 1960s, concerns about population concentration in Seoul have grown due to its proximity—only 40 km from the border with North Korea. In response, the South Korean government wanted to decentralize the spatial structure of Seoul and move administrative functions to the southern part of the country. As part of this effort, the government initiated a new administrative capital plan, with one team led by Kahng. His research, published in “A Study for Urban Problems and Urban Patterns,” addressed the challenges faced by the city and proposed potential countermeasures (Kahng et al., 1979; Lee, 2009).

This study identified the basic types of land use and road network of cities and aimed to analyze the relationship between urban problems and urban patterns (see (a) in <Figure 7>). Kahng concluded that linear patterns held the greatest potential for addressing urban issues (Kahng et al., 1979). The findings of this analysis likely reinforced his belief in a linear city concept. At the end of the report, he proposed a plan for a linear commercial area to accompany the proposed new administrative capital (see (b) in <Figure 7>).

Figure 7.

Study and proposal for new administrative citySource: Kahng et al. (1979)

4. Rosario Metropolis for Seoul in 1980

In addition to addressing the need for spatially distributed structures as 1977 plan by Kahng, there was also a pressing need to tackle the housing shortage and car-centric transportation. When Kahng (1980b) unveiled the Rosario plan, it was titled “ROSARIO METROPOLIS FOR SEOUL 2001,” and he referred to the plan’s figure “the ROSARIO metropolis of tomorrow”, clearly indicating that the plan was essentially a metropolitan-level initiative. This plan was based on the idea of “transit and housing,” linking subway construction with housing supply through a “value-capture” strategy, which is crucial for developing countries with limited capital (Sung and Choi, 2017).

Kahng criticized Seoul’s existing decentralization strategy, which relied on a radial network based on the current road system (Kahng, 1980a; 1980b). Instead, he proposed constructing a distributed structure in Seoul using the multi-directional magnetic fields created by each station: “the Rosario system with several series of crystallized beads they are; however, they do not converge into any single center. They are different from underlying road patterns which converge into the center focus. They may seem converging into a point where “strings” will meet, but there is not only one, but might be numerous” (Kahng, 1980b: p.502).

The Rosario Plan also incorporates district-level details of TOD. Sung and Choi (2017: p.519-520) evaluated the Rosario Plan based on the five Ds of TOD, asserting that the station area prototype closely resembles Calthorpe’s TOD (see <Figure 8b>). To meet the rising population and housing demands in Seoul, the plan calls for the development of high-density apartments in the station area. This area should feature mixed commercial and residential uses to achieve land use ‘diversity,’ while also allowing for the presence of light industrial facilities. A district-level approach is necessary, accompanied by a comprehensive ‘design’ for the station area. If the plan’s target population density is reached, it could accommodate about 8.6 million people, ensuring ‘distance to transit.’ Additionally, the proposal includes measures to limit vehicle traffic and enhance the pedestrian environment in the subway station area to achieve effective ‘demand management.’

Figure 8.

Rosario Metropolis of Tomorrow for SeoulSource: Kahng (1980b)

The Rosario Plan was included in the first official compre-hensive plan for Seoul in 1990, established under South Korea’s urban planning law. In this plan, Prof. Kahng contributed to the planning of land use and spatial structure. His proposal focused on the development of the station center, and it was included in the Seoul city plan (Seoul City Government, 1990). Since 1995, Seoul City has been up-zoning areas around subway stations for over 20 years, encompassing a total of 252 sites and covering an area of about 39 hectares (Yun and Choi, 2021). Recent studies have quantitatively shown that the floor area ratio in the up-zoned catchment areas of subway stations has increased more than in other areas (Yun and Choi, 2021; Kim, 2022). While not directly linked to the Rosario Plan, Seoul City has been actively promoting development around subway stations in recent years.

5. Mok-dong New Town Concept in 1983

In 1983, the city of Seoul began developing a large-scale new town spanning approximately 430 hectares in the Mok-dong area, which was a low-lying region prone to flooding and challenging for development, in response to rapid population growth. At that time, the city sought to select a design team through a design competition, a practice that was quite rare in Korea. Byeong-Kee Kahng and Oswald Nagler, who served as an advisor to the Housing and Urban Research Planning Institute (HURPI) from 1965 to 1967, were commissioned by the city of Seoul to create a basic concept design prior to the design competition (Kahng, 1993). The design developed by the two was based on the ‘linear city’ model.⁶⁾

Whether it is merely a coincidence is unclear, but two proposals based on the linear city model in the Mok-dong design competition were considered superior.⁷⁾ As a result, the actual planning and development proceeded by creating an integrated design that capitalized on the strengths of both proposals while addressing their weaknesses (Kahng, 1993).

Recently, Jung and Hong (2024) confirmed that the linear structure implemented in the new development of Mok-dong significantly influenced the district planning of new towns in the Seoul metropolitan area, as well as Sejong City. They revealed that Mok-dong’s design concept had a significant influence on Bundang’s ‘service axis’ concept through their conversations with Yeong-Te Ohn, the urban designer of Bundang, which is the most iconic and largest of the first-generation new towns in the Seoul metropolitan area. They further show that this concept has evolved into a ‘community corridor’ in the second-generation new towns.⁸⁾

1. Linear City

A review of the plans prior to Prof. Kahng’s proposal of the Rosario Plan indicates his strong conviction in the linear city concept. His belief evolved according to the given conditions. The 1977 proposal was based on the assumption of a metropolitan city with a population of about ten million which was reflected in the two rings connecting both sides of the line, including the existing city center. In contrast, the new administrative capital plan for a one million population in 1979 adhered to the traditional linear city model, developing linearly along the axis of urban growth.

Since Soria y Mata, many planners have embraced and implemented the concept of linear cities; however, proposals for a circular spatial structure have been rare. Aside from the 1977 plan and the Rosario concept, there are two plans that coincidentally emerged from the 2005 international competitions for the new administrative capital of Korea.

Prof. Kahng described the basic concept of the Rosario Plan as a “string,” suggesting that it could resemble a necklace by connecting it like beads (Kahng, 1980b; Sung and Choi, 2017). He proposed a ring structure that more actively links Soria y Mata’s original proposal to a subway network. However, as illustrated in <Figure 8a>, it is challenging to fully explain all the distributed structures centered around the various transitions in the Rosario Plan.

2. Transit for Metropolis (TOD and TOM)

Howard’s “Garden Cities of Tomorrow” carries significant meaning as a social movement (Fishman, 1982). From a spatial perspective, it envisions a metropolitan area connected by a canal and railroad network, with cities designed to achieve self-sufficiency within walking distance of factories, shops, farms, and more. So, Hall (2002) argued that Calthorpe’s TOD may have drawn inspiration from Howard’s ideas as well as European metropolitan plans developed in line with Howard’s spatial planning concepts.

When expanding a metropolitan area, it is crucial to address the transportation network. Tange’s 1960 Tokyo Plan emphasized the smooth flow of automobile traffic, while TOD and TOM advocate for utilizing public transit networks and organizing activities and land use around transit station nodes. Three years prior to the announcement of the Rosario Plan, Kahng recognized the limitations of car traffic in his spatial plan for Seoul and proposed creating a spatial structure based on a railroad network (Kahng, 1977). His analysis highlighted the clear limitations of expanding the road network in existing urban areas, confirming that a significant shift toward a railroad system is necessary to address transportation challenges in the metropolis (Kahng, 1977).

If Howard’s proposal, along with Europe’s and Japan’s TOM, utilized a railroad network to connect new and old towns, the Rosario Plan not only encompasses this concept but also serves as a means to facilitate change within existing towns. The Rosario Plan suggested that the station and its surrounding area should be leveraged as catalysts for urban renewal and redevelopment.

Kahng’s continuous studies in Japan from 1947 to 1970, spanning high school to his Ph.D., likely had a significant impact on the development of his Rosario concept. During this period, he witnessed numerous post-war restorations and urban developments in Japan. Tokyo has a prominent example that has integrated the Garden City movement with mass transit. While the Japanese concept of TOM incorporates aspects of urban development by private rail-road companies (Yorihusa, 1987), the Rosario Plan distinguishes itself by emphasizing public development, urban planning, and value capture (Sung and Choi, 2017).

3. Semi-lattice Spatial Structure

Before proposing the Rosario Plan, Kahng moved away from the Cartesian perspective he held in his youth and developed an understanding that urban diversity should focus more on people’s daily lives (Kahng, 1993). His skepticism toward modernist architecture and urban planning began in 1977 when he participated in the affordable housing plan for Jahra, Kuwait (Lee, 2007). In this project, he oversaw the planning of a housing complex for indigenous people, realizing the necessity for planning and design to align with the users’ needs rather than the designer’s viewpoint (Kahng, 1993). This experience spurred significant changes in his thoughts on urban design and planning from the late 1970s onward.

His two articles from around 1980 demonstrate a complete transformation in his thinking. “Loose System” (Kahng, 1979) introduced the semi-lattice structure originally proposed by Alexander, while “From Mono to Multi” (Kahng, 1981) embraced diverse and pluralistic values. This shift in perspective led him to explore the potential of using the subway as a means of public transportation to effect change.

This idea was incorporated into the first comprehensive plan for Seoul in 1990, which included the Rosario Plan and reflected Alexander’s semi-lattice structure (see <Figure 9>). The plan aimed to distribute the centers of both large and small city activities through the use of public transportation, while emphasizing the subway and road networks as essential elements for structuring developed living spaces (Seoul City Government, 1990).

Figure 9.

Concepts for spatial structure for Seoul in 1990Source: Seoul City Government (1990)

4. Urban design

The Rosario Plan included diagrams that provided a detailed design of the station area (see (b) in <Figure 8>). The prototypes featured in this plan discussed the Ds of TOD, incorporating more thorough urban design at both the district and metropolitan levels, as elaborated in previous sections of this article. Kahng himself identified as an urban designer (Kahng, 1980b) and developed an interest in urban design during his time at Tange’s lab around 1960. He stated that his motivation for returning to Korea in 1970 was to practice urban design in his homeland, and he made various efforts to introduce urban design concepts to the country throughout the 1970s and 1980s (Kahng, 1993; Lee, 2009).

Just before proposing the Rosario Plan, Kahng published “Definition and Range of Urban Design” (Kahng, 1980a). This article provided a comprehensive introduction to urban design in Korea, outlining its significance and necessary actions with detailed explanations. As one of the pioneers of urban design in Korea, he became the first president of the Urban Design Institute of Korea in 2000, which was the country’s first academic association dedicated to urban design. His diverse interests and expertise in urban design are reflected in the concepts of density, diversity, and design included in the Rosario Plan.