While the intent of my Focus articles is normally to share information about current exhibitions on Japanese architecture, we are still feeling the effects of the Covid-19 restrictions and their limitations on organized events. Fortunately there is no limit to what we can see and experience of Japan's architecture simply by observing our everyday living environment. Every detail of what surrounds us has a story behind its existence. On this occasion, I would like to take a closer look at the profusion of green rooftop gardens among the retail buildings of Tokyo.

While recent green-building initiatives have helped enormously in the greening of buildings globally, the architecture of Tokyo in particular has been providing green rooftop escapes for nearly a century. To understand the reason for this, let's look back at the history of parks and green spaces in the capital. Compared to other global cities, Tokyo has a far lower percentage of green space out of its total land area. While a city like London has approximately one third of its area covered by parks, only about seven percent of Tokyo is green space. Historically, Japan does boast a rich tradition of garden design, but this was more the exclusive domain of upper-class patrons. The reason for the very low proportion of urban greenery in Tokyo, and Japanese cities in general, is that the concept of municipally sponsored public park spaces in cities did not reach Japan until after the advent of the Meiji Restoration in the late 19th century. So even though parks for the purpose of public enjoyment, such as Hibiya Park in downtown Tokyo or Yamashita Park in Yokohama, were eventually introduced in the early 20th century, Tokyo has remained an extremely dense urban metropolis with comparatively little park space.

The 1930s saw a huge building boom in the aftermath of the Great Kanto Earthquake of 1923, and along with the greater safety offered by concrete structures, the advanced technology allowed department store operators to entice shoppers with magical green oases on their rooftops. Mitsukoshi Nihombashi, Mitsukoshi Ginza, and Isetan Shinjuku are all examples of major stores dating from this era that featured green rooftops which still exist today in one form or another. Perhaps because of our modern shopping habits, where an hour can seem like a long time to stay in one store, we can only imagine the excitement of residents of the greater Tokyo area who would devote a day to travel to these new and marvelous places. You might say they were the precursors of our amusement parks today. Based on the great success of such buildings, department stores of postwar Japan embraced the concept further. Nowadays any department store you visit in Japan is almost sure to have some type of rooftop amenity, be it a park or a beer garden, which is yours to discover and enjoy.

In addition to the amusement provided by these green spaces, an interesting commonality shared by many rooftop gardens is the presence of a Shinto shrine. Retail building owners welcome the auspiciousness of having a shrine on their rooftops, which simultaneously provide a solution to the problem of what to do with existing shrines located on land with premium retail value. Even amid the extreme density of Tokyo, shrines have traditionally been swathed in a cocoon of greenery, away from the hubbub of the main thoroughfares. Therefore, while this remote placement of a religious element might seem strange to a foreign visitor, a rooftop garden is actually quite suitable as a location, and the function of a Shinto shrine as a link to nature has helped to substantiate the use of these green rooftops as shrine settings.

One interesting example of a rooftop shrine is the Omiwa Shrine located atop the west wing of the Komatsu Building in Ginza (shoppers are probably more familiar with its east wing, connected by a bridge, which is Uniqlo Ginza). A visit to the top floor of the building takes one to a unique and meditative environment, its mystique all the more accentuated by the fact that it floats above the hectic bustle of the Ginza.

Recent government incentives to mitigate global warming and heat-island effects should encourage retail building developers to continue to embrace this long-established tradition of providing green space on rooftops. In addition to offering amenities that attract shoppers, nowadays integrating greenery into buildings has become a valuable tradeoff for developers wanting to receive exemptions from building area restrictions through special planning agreements. An example of this is the expansive rooftop park of Ginza Six Garden. The entire perimeter of the park is planted with greenery, allowing one to take a garden stroll around the building and enjoy a 360-degree view of the city skyline in the bargain. It is an impressive design endeavor reminiscent of the ambitious garden spaces of the past.

Fortunately for us, the practice of incorporating beautiful green spaces into the architecture of retail buildings is no longer limited to large-scale department stores. Perhaps one of the most pastoral rooftop gardens in Tokyo is that of Tokyu Plaza Omotesando. The living room-like furniture set within the carefully designed stepped garden subtly faces inward to form a comfortable enclosure of green. Also created by the same retail developer is Tokyu Plaza Ginza, which offers spectacular views of the city from an outdoor patio and reflecting pool surrounded by greenery that floats overhead, supported by the perimeter's structural frame.

Green park-like amenities integrated into retail buildings seem to be growing into an ever-stronger attraction for the public today. This is evident in the most recent projects, such as Tokyo Midtown Hibiya, Shibuya Parco, and what is by far Tokyo's largest rooftop garden to date, Rayard Miyashita Park in Shibuya. Tokyo readers no doubt have green escapes of their own besides those mentioned in this article. Nevertheless, I hope that this look at the green rooftops of Tokyo will inspire you to take a detour on your next shopping trip in the city to discover some of the lush gardens hidden in the most unlikely of places.