1. Introduction

This thesis is about small public spaces in Tokyo. Tokyo is a city known for many contrast: large scales vs. small scales, commerce vs. tradition, and vast areas of dense urban sprawl vs. a scarcity of open space. For the increasing interest in the progression of open spaces development there is yet an additional contrast: whereas privately-owned spaces in lucrative locations constantly attract enormous crowds, abundant small public parks are hidden behind the dense urban fabric and widely unnoticed by the public audience. This demonstrates an evidently paradox situation: privately-owned spaces become the authentic public spaces while official public parks turn out to be deserted places. The fact that Tokyo lacks public open space on the one hand, whereas numerous small parks are not serving peoples demands on the other hand, shows a serious, uncultivated potential.

Since E. F. Schumacher published his book "Small is beautiful" in 1973, arguing for human-scale concepts in economies, the appreciation of smallness grew in many disciplines. Jane Talbot (1988) argues that "In many artistic domains, the small form is considered the most demanding and the closest to perfection: in poetry, the haiku or sonnet". (p. 290) Both the challenge and degree of perfection can certainly be affirmed for numerous traditional Japanese gardens as well. But what happens in the public realm? If we transfer the concept to open spaces in Tokyo, is small still beautiful? If we look upon Tokyo's uncountable small parks we see a wide range of qualities: there are good examples and less convincing examples. Yet, what these parks generally are missing is a collective quality- a powerful statement of their importance for the people.

It might be suggested that the full potential of small public spaces in a mega-city such as Tokyo is only evident, if miniature spaces get a face in the giant urban fabric. They need an authority.

2. Question , assumptions and hypothesis

The aim is to identify (new) approaches in designing small public spaces and to point out potentials respectively. This research examines spatial and design issues from the perspective of landscape design. In the center of interest are the questions:

to what degree do size and other spatial structures affect the quality of small urban spaces?

how do these conditions influence the design process?

Two claims have been made to answer the research questions. The first claim is that the interrelation of spatial parameters at small public spaces is very complex so that with smaller size, the impacts of certain surrounding parameters become more important (Space-Space challenge). The second claim is that spatial impacts on the small open space challenge design processes regarding creative, functional and economic considerations (Space-Design challenge, Space-Function challenge, and Space-Economy challenge)

Deriving from these assumptions the hypothesis is that

due to physical constraints, small public spaces require particular design concepts and considerations in order to generate quality solution, which support their potential.

3. Method

The research subject comprises theoretical and practical issues in landscape design, urban planning and environmental behavior. A qualitative research approach was chosen in form of the case study method with multiple units of analysis. These include 1. literature review, 2. the investigation of 142 small spaces (<300m2) in four case study areas in Bunkyo, Meguro, Taito and Toshima wards, 3. explanatory surveys (oral/written) at Park and Greenery Sections within the four ward administrations, and 4. semi-structured in-depth interviews with nine renowned landscape designers.

The case study analysis focuses on the evaluation of the spatial qualities of small public spaces in Tokyo, for which each site was analyzed in terms of its positive, negative or neutral inclination concerning quality criteria and finally clustered into similar qualities.

The interviews obtain a comprehensive spatial analysis, testing the theoretical concepts of production and revealing objections concerning small urban spaces in Tokyo : For the analysis, interview data were transcribed and coded in order to arrive at themes and typologies, describing the respondent's attribution of space and their design process.

4 Findings

4.1 Spatial theories

The greater environment can be considered as a pile of smaller fractions, thus in order to value small spaces it is necessary to understand the larger environment. Scholars in environmental psychology and spatial analysis point out that preferred environments, first, are decodable via borders and spaces in-between and, secondly, express a degree of attraction that evokes the sense of connectedness and involvement. The first refers to the concept of space, the latter one to the concept of place. Landscape architectural professionals interviewed for this thesis support these concepts. The question how landscape designers define space, and about their most important considerations when dealing with it revealed that space is only the "starting point" or existing precondition for the profession to alter or manipulate the landscape into some meaningful place. Thus, space is not in the center of interest anymore, as the emphasis is laid on the sense of place. Consequently, the interviewees' definitions included aside from core properties (addressing space) also information on transitional and design properties (defining the characteristics of place). (Fig 1)

Deriving from the theoretical analysis, following six spatial and design considerations proofed to be essential quality criteria for small public spaces in Tokyo.

4.2 Evaluation of small public spaces in Tokyo

The scarcity of public open space in Tokyo and increasing importance of large privately-owned public spaces evokes the need to concentrate again on public open spaces at "the basis", in local neighborhoods, where the people are. Rooting in the first creation of public spaces at the beginning of the last century, numerous small public parks have already been created in many neighborhoods throughout the city. However, changing urban contexts and social demands increasingly put pressure on these places and require alternative concepts and solution in their design.

The evaluation of small public spaces in Tokyo was based on quality criteria shown in table1. Five quality categories could be found:

1. Positive tendency spaces indicate a high degree of complexity and mystery while simultaneously demonstrating spatial coherence and legibility.

2. Peculiar spaces illustrate on the one hand remarkable spatial situations, which are on the other hand not yet fully acquired.

3. Undefined spaces reveal a lack of definition either in terms of spatial formation or in terms of functional determination; coherence and legibility are reduced; in some cases, however, the design improved the evident deficit.

4. Substandard places miss a statement and justification for an open space function, often both sense making and involvement are not identified.

5. Mediocre places present a medium level of spatial and design quality; their physical conditions are easy to decipher, but present limited stimuli and possibility for involvement

This investigation reveals that several examples already imply alternative approaches and generate a few positive places. These spaces include e.g. distinctive solutions, successful interaction with the surrounding environment and a statement towards changing social demands. Other examples draw their better performance form spatial conditions with positive potential, which call for a mitigation in design solutions. So far, these interventions are however, only individual phenomena without broader effects on the city.

Conventional approaches focus on quantities rather than qualitative solutions by creating generalities for better efficiency. The design for small spaces therefore becomes also very political. Moreover, it proves that with smaller size, the impact of surrounding parameter on a site becomes more important and that a dominant surrounding environment evokes the risk for the small open spaces to loose its autonomy in the urban setting. The interrelation of spatial parameter at small public spaces are therefore more complex compared to large spaces- especially concerning the balance of inside and outside and the importance of boundaries. Design concepts and considerations for large public spaces can only partially be applied on small open spaces.

5. Conclusion

This thesis concludes that there are spatial, design, socio-functional and political-economic constraints challenging the quality and design of small public spaces, which can be summarized in four categories:

a) Space - Space Relation: Ensuring autonomy of small open spaces

One of the most influential parameter on small open spaces is the degree of enclosure. This defines, first, whether the site is perceived as a positive or left-over space. So far, small public spaces in Tokyo are predominantly located in low to medium rise residential districts, which provide a fairly good environment to develop their potential considering the limitation in size. Yet, there are already numerous examples of conversion where small spaces have lost their autonomy in the urban fabric, turning into isolated and disconnected places.

b) Space - Design Challenges: Enforcing spatial definition of small open spaces

Small public spaces have in general a high degree of coherence and are decidedly legible. On the other hand, the examples in Tokyo often face a lack of complexity and mystery. Since exterior conditions present little variety, it is only possible to differentiate parks through interior conditions, which would require individual designs.

c) Space - Function Challenges: Generating meanings for small open spaces

Rather than merely developing physical conditions (constructing spaces), there is a need to focus on creating meaningful outcomes (production of places). Visualization of time and the possibility for human intervention and alteration come into focus. In this context, conventional open space functions are quickly confronted with their own limitations and need to be reconsidered. For small public spaces, alternative utilizations are therefore required, which additionally need to reconsider images, identities and contexts and that emphasize the peculiar "feeling" of a place.

d) Space - Political/Economic Challenges: Regarding small open spaces as necessity instead of an amenity

First, there is the emphasis on strong separation between public and private interests resulting in extremely controlled situations; secondly, governments addressed their desire for efficiency concerning implementation and maintenance management; and third, rigid planning regulations emphasize on quantity rather than on quality aspects. The majority of small parks still manifest conventional planning strategies. Thus so far, small public spaces have been considered as an amenity rather than a necessity to serve local neighborhoods in Tokyo.

7. Suggestions

The main conclusion that can be drawn from this thesis is that, although small spaces function on a local scale, they can yet not be regarded isolated. In contrast to large open spaces as self-sustaining entities, the real potential of small parks only derives from the broader connectivity. There is an evident need to formulate the authenticity of small public spaces in Tokyo's urban landscape. Regarding statements on design this would address two levels: on the small-scale local level the open space should open to its surrounding in order to attract involvement. On the large-scale city level small spaces should be connected in a resourceful diversity network, which formulates the genuineness of small public spaces, while accentuating each site's individuality.

Fig 1: Three levels and subcategories of landscape architectural space as derived form interviews with professionals

Table 1 quality criteria as basis for the evaluation of small public spaces in Tokyo

Fig 2 &3: Qualities of small public space: positive tendencies (left), substandard places due to difficult space (right)

本論文は、東京という高密な都市の構造の裏側に隠れ、多くの人に気付かれることなく、また使われずにある小さな公共空間(公園)に焦点を当て、小さな空間に秘められた可能性と意味を検証するとともに、小さな公共空間をデザインする際の新しい手法を提案することを目的としている。

本論文は、序章(1章)、2章~7章、結及び提案(第8章)から構成されている。

第1章では、1973年にE.F.Schumacherがヒューマンスケールの観点から経済の考えを主張した"Small is beautiful?"という概念を、現代の東京の空地にあてはめた場合、"Small is beautiful?"という概念は正しいかと問題提起した上で、研究の背景、目的、研究方法、論文の構成、について示している。

第2章では、ランドスケープの視点を取り込んだ空間について、専門家の事例をあげながらその特質について記述している。ランドスケープにおける空間の質を明らかにするために、専門家とのインタビューを通して「Core Properties」「Transitional Properties」「Design Properties」という3つのレベルと、さらに下位に分類されるランドスケープの空間要素を導き、設計上のテーマとタイポロジー導き出している。

第3章では、東京の小さな公共空間の具体的事例の調査・分析を行なっている。敷地の規模、境界、周辺環境などの空間条件が、小さな公共空間をどのように規定し、そこに生み出されたデザインとの相互関係について考察を加えている。

第4章では、ランドスケープの空間の質を決める要因について考察している。空間そのものではなく、意味のある場所とランドスケープその相関関係が空間にとっての最も重要な質であり、場所の重要性を明らかにしている。また、東京の小さな公共空間の特質とデザインをあらわす6つの評価基準(spatial interaction, embracement, geographic features, composition, restorativeness, social interaction)とデザインエレメントを見出し、小さな公共空間をより良くデザインする方法について述べている。

第5章では、東京の小さな公共空間の歴史的な形成過程について述べている。

第6章では、ケーススタディとして、東京の中心部に位置する4つの区(台東区、文京区、目黒区、豊島区)に位置する小さな公共空間をとりあげ、その歴史、社会的、政策的な観点からの形成過程および利用状況等を調べ、それぞれの空間の質とデザインを、評価基準に照らし合わせて検証・分類している。

第7章では、小さな公共空間に対する新しいデザインアプローチについて9つの提案を記している。また、小さな公共空間の新たな可能性を示すキーワードとして、1)変化の可能性、2)個と公の流動性、3)ヴォリュームとしてのオープンスペース、4)広い接続性、5)ブランドの創造、の5つを提示している。

第8章では、結論として、小さな公共空間の質やデザインをより良いものにする為に取り組むべき、空間、デザイン、社会的機能、政治的経済的課題について説明した上で、周囲の住人や環境を取込み、相互作用を促してながら周囲へと開かれていくことの重要性を述べている。そして柔らかな境界の在り方と質の高いデザインを併せ持つ小さな公共空間が、個性的な存在感をもって立ち現れることが、東京という都市における公共性にとって必要不可欠なことであることを示している。

以上のように本論文は、これまでデザインの対象としても、また都市における公共空間としても評価されにくかった小さな公共空間(公園)を研究対象として選び、そこに展開されているデザイン手法を具体的に調査し、空間的な特質を評価する基準を提示してみせた。その上で、新しいデザイン・アプローチの可能性を提案し、東京のような都市における公共性において、小さな公共空間の持つ潜在的な可能性を明らかにした。建築設計学の分野においてのみならず、都市計画の分野においても、大いに寄与するものである。

よって本論文は博士(工学)の学位請求論文として合格と認められる。