View from Roppongi Hills Mori Tower

Izaka Hills is a concept proposal for the planned redevelopment of the Roppongi 5-chome West district in Minato-ku, Tokyo.

For Tokyo’s first redevelopment of this scale to be planned since the coronavirus pandemic, it is prudent to reevaluate the goals of such sites:

In the age of remote work, cities can’t take for granted that people will need to come to work and therefore live nearby. So instead, cities must work to emphasize their strengths – the things that bring people together – so that people want to live in, work in, and visit the city.

To this end, Izaka Hills’ primary design consideration is how to nurture community amongst its residents, workers, and neighbors.

View from Roppongi Hills Mori Tower

Inspired by Minoru Mori’s interpretation of Le Corbusier’s “vertical garden city” concept, the majority of building floor area is concentrated in two towers, one at each end of the site, opening up space for a large tiered garden to be framed in the center.

The Roppongi 5-chome West site is one of contrasts:

• More than half a kilometer long while only 150 m wide
• A bustling commercial road abuts its northern border while a quiet residential neighborhood lies to its east
• A steep change in elevation of 20m exists from its east side to its west side

Izaka Hills’ buildings and landscaping are deliberately shaped in response to these contrasts:

• The steep change in elevation is leveraged to create grade-separated pedestrian and vehicle traffic flows
• Buildings and dense greenery are massed so as to shield the central garden and residential areas from the bustle of bordering commercial streets
• Key sight lines from Roppongi Hills to Tokyo Tower are preserved

Cutaway view

But Izaka Hills is more than meets the surface.

Continuing the principles of the vertical garden city, space underground is used just as deliberately as the space above ground:

• A grade-separated pedestrian network connects the entire site with neighboring subway stations to the north and south, allowing barrier-free and umbrella-free access to the transport nodes of Roppongi Station and Azabujuban Station.
• A world-class all-weather sports complex and multi-purpose assembly hall are woven through the foundations of the low rise buildings and under the central garden.
• Sunken gardens framed by their respective buildings provide private outdoor spaces to the site’s school and to its cultural institution.

View eastward along Gaien Higashi-dori

It all starts with the Main Tower and the sloped “Metro Root” building which connect the site with the landmark Roppongi Crossing, framing a new icon on Gaien Higashi Dori.

These buildings house offices, residences, a hotel, meeting/convention facilities (MICE), and commercial space for associated business such as restaurants and convenience stores.

Traffic flows

The Main Tower and Metro Root combine to form a multi-modal 3D transport node connecting the site with Roppongi station and with the surrounding roads.

By leveraging the difference in elevation between the northeast and southwest of the site, connections are made between the complex and the roads on its northern and western borders while also connecting those roads to each other, all in such a way that intersections are minimized for optimal traffic flow. A further benefit of this arrangement is that it requires no driveways to be placed along the quiet residential street along the site’s eastern edge, helping to minimize the presence of this large complex on the neighboring residential area of Roppongi 5-chome East.

Despite the attention given to optimizing vehicle traffic flow, pedestrian flows are equally considered, with barrier-free connections established between the site, Roppongi station, and the surrounding neighborhoods. In addition to access via the grade-separated open-air pedestrian plaza, an enclosed passageway is woven into the 3D road system in order to provide umbrella-free connectivity between the site and the station on days with inclement weather.

View westward along Gaien Higashi-dori

Inspired by the form of Japanese castles, a sloped stone foundation surrounds the Main Tower along Gaien Higashi-dori, topped by a contrasting low-rise building. However, unlike a castle, the stone wall is perforated by storefronts and entrances to welcome in the community.

Sitting atop the sloped walls, the low-rise podium building’s insets between floors reference the design of the building currently located in this spot while the entrance responds to that of Azabudai Hills, located diagonally 400m along the same road.

View southward towards Toriizaka

Just meters away from the bustle of Gaien Higashi-dori, low-rise buildings and ample greenery complement the existing low-rise multi-family residential neighborhood along the site’s east side.

This side of the site is entirely free of vehicle entrances, helping to maintain the tranquil atmosphere of the existing neighborhood. However, pedestrian entrances are provided in order to improve access to nearby public transport and to the surrounding area.

View westward at Toriizakashita

On the southern end of the site, the Residential Tower hosts businesses essential to daily life on its first four storeys before sloping gracefully back to its tower form.

Doctors, dentists, a pharmacy, pet care, groceries, and other essentials of a rich and healthy life are close at hand.

The deep stepped-back terraces bring an advantage to living on the lower floors of a residential tower by providing ample outdoor space in the city center for those who like to maintain their own plants.

View northwards towards Imoarai-zaka

Ascending gradually in height as they approach the Main Tower, the collection of buildings along the site’s western edge serve a variety of functions, hosting boutique retail and dining in the three storey buildings near to the lower park while commercial retail and a library are housed in the building topped by a semi-honeycomb lattice closer to the Main Tower.

Main garden

Concentrating the majority of floor area in the towers at either end allows for an expansive garden to extend through the center of the site.

Inspired by Wasabi fields in Izu, the tiered garden provides a green oasis in the city center, with separate paths laid to meet the different needs of visitors and residents.

The five-tiered waterfall aligns with Tokyo Tower not only within the site but also from Roppongi Hills’ pedestrian bridge across Keyakizaka dori, creating a photogenic scene from locations across the neighborhood.

Residential garden

Although not divided by walls, the central garden is shaped to allow different portions to serve different functions.

In the residential area, a daycare and preschool open out to a children’s playground nestled between the Residential Tower and the locals’ museum.

Residents’ museum

MUSEUM SUZUME is one of several features of the site designed to create community: a third place to socialize outside of the home and work/school.

Although the site’s neighborhood of Roppongi is replete with museums hosting renowned works from around the world, this museum is of and by the locals: it will host classes for and exhibit the creative works of community members, building connections and hopefully even sparking friendships between those who might otherwise never have had occasion to speak due to the often anonymous dynamics of life in an apartment tower.

Classes targeted at different age ranges and languages would be given in various media throughout the year. At the end of each course, each student would select one of the pieces they created to be exhibited in the gallery space for an interval which would include an “opening event” to welcome family and friends of the class members to view the works and socialize.

Library main level

No community is complete without a library. Beyond a building to house print media, a good library should serve as a space for both inspiration and concentration.

Izaka Hills’ library sits on the upper floors of one of its commercial buildings, and is shaped into sections tailored to the needs of different age groups.

The library channels its location in an international neighborhood replete with embassies by offering rotating exhibitions and collections to highlight different cultures from around the world.

A mural illustrating the constellations of the night sky adorns the building’s uppermost ceiling. Inspired by the “Celestial Ceiling” of New York’s Grand Central Terminal, it hopes to open the aperture of visitors’ imaginations and, as it peeks through the atrium, to draw visitors through and up into the building.

Library upper level

One of the primary goals of the library is to create a safe and constructive space to nurture the growing independence of teenagers and young adults.

Drawing upon the same concepts as university libraries, this section provides individual and group study space along with various collaboration spaces for schoolwork and social interaction outside of school and home.

Athletics complex

While the site’s neighborhood of Roppongi is replete with a variety of cultural institutions, one area in which it is lacking is in athletics. Moreover, Tokyo’s climate is not the most conducive to year-round fitness, with increasingly hot summers and a pronounced rainy season making consistent outdoor fitness challenging.

In response to these challenges and thanks to the unique shape of the site, a world-class all-weather fitness facility is installed under the central garden, providing a full-size track and courts for sports such as soccer, tennis, and basketball, while an 8-lane 25m pool is installed in the center of the Residential Tower.

In an era where many jobs can be performed remotely, highly-skilled workers often have many alternatives open to them should their current employer attempt to force them to come back into the office by mandate. However, by offering access to the site’s first-rate lifestyle facilities and programming to their employees who work from the office, firms who take office space at Izaka Hills will be able to offer an unmatched collection of benefits with which to entice (rather than to coerce) their high-performing teams to come together in the office.

Home office

While digital collaboration technology allowed an impressive amount of work to continue in spite of the lockdowns of the COVID-19 pandemic, the abrupt shift to working from home saw many people having to work from cramped and often unideal makeshift home offices, crammed into a corner of a room already being used for other purposes, such as a bedroom or a living room. These challenges were compounded for those who live with a spouse or partner who also needed to work remotely.

Finding room for a proper home office setup is particularly difficult for families who live in apartments, as their limited floor area is often divided only among a living room, kitchen, bathroom, and bedrooms. To the extent that some apartments have a separate space for a home office, it is often a small and windowless den or nook.

This reflects the inherently-limited amount of space bordering apartment buildings’ exterior walls wherein outward facing windows can be installed. And as a building is scaled to a larger footprint, the ratio of its area within a fixed distance of its perimeter scales less than linearly, compounding the challenge.

For these and other reasons, many larger apartment buildings have a hollow core around which the hallways of the building are wrapped. While some buildings feature open-air hallways that allow a room or two of each of their apartments to look out onto the central courtyard, this is often considered undesirable since the hallways are exposed to the elements and the inner windows look out onto the hallway, decreasing the privacy of the home. As such, many high-grade apartment buildings opt for enclosed but windowless corridors, thereby missing the potential to bring more natural light into the building.

In response to these seemingly irreconcilable factors, the Izaka Hills Residential Tower introduces a new concept: the Trunk Office. Just as many apartment buildings feature storage units (“Trunk Rooms”) that are separate from the apartments themselves, these Trunk Offices are rooms suitable for use as a home office located within the same building but separate from the individual apartments.

This separation has several benefits, starting with the fact that it allows them to be placed on the opposite side of the inner corridors, enabling windows to be added facing the inner courtyard without the disturbance of people walking directly in front of those windows. And while the view of an enclosed courtyard may not be the most inspiring, the natural light afforded is certainly preferable to a windowless room.

Separating the home offices across a corridor from the apartments also provides a degree of privacy not afforded by most home offices: the sounds of the home and of the office are isolated from each other, allowing children to play as normal without fear of disturbing their working parents and allowing working parents to take early-morning or late-night calls, such as with colleagues in different time zones, without disturbing their families as they sleep.

Finally, this arrangement enables greater flexibility to respond to changes in demand for home office space, since the Trunk Offices are leased separately from the apartments. For example, if a family changes from having no need for a home office to having one parent start remote work and then the other parent also start remote work, the family can start leasing first one and then even two Trunk Offices all without the need to uproot their family and move apartments each time their needs change.

Residential Tower corner

While the boxy and repetitive form of most modern buildings can lead residents of cities to a complacency with such structures which would have once inspired awe, Izaka Hills seeks to reward those who still have the curiosity to look up at the towers of their city, with a series of elements designed to entice even greater interest on the second glance.

For example, the northeast corner of the Residential Tower is softened to a curve by following a step function. This step function is derived from a curve that is used repeatedly throughout the site: from the sloped base of the Residential Tower to the roof-supporting planks of the SUZUME MUSEUM. When viewed from the correct angle on the ground, this modulated corner recreates the outline of a ginkgo leaf resembling the Symbol of Tokyo.

View from Tokyo Tower Top Deck

Through the design of its buildings, infrastructure, and programming, Izaka Hills seeks to further improve Tokyo by carefully building community, responding to evolving workstyles, and not only complementing but enhancing its surroundings.

This is done in the aim of helping to nurture in those who live in, work at, or visit Izaka Hills, the project’s ultimate goal:

An inspired mind in a vivacious body.

A note on preservation

The plan depicted herein would require the relocation or reconstruction of the International House of Japan (IHoJ) and its beautiful garden. This is not a decision proposed lightly.

Growing up in a suburb of New York City, my gateway to that metropolis was the iconic Grand Central Terminal. Despite passing through countless times, I am still struck by the ambition and beauty of its design and craftsmanship. The uplifting grandeur of Grand Central stands in stark contrast to New York’s other main train station, Penn Station, which consists of a maze of cramped, dark, and chaotic passages seemingly inserted as an afterthought under the Madison Square Garden arena. And so I was shocked when I learned that there had once been a Penn Station of the same order of Beaux-Arts beauty and passenger experience as Grand Central, but that it had been torn down to make way for the current depressing complex. I was even more shocked to learn that there had been a similar plan to demolish Grand Central and am heartily grateful to those who prevented it, in an example where preservation was clearly preferable to replacement.

At the same time, cities cannot be entirely preserved in their current states in perpetuity. Cities exist to enable the activities of people, and people’s needs and lifestyles change over time, just as new technologies evolve which enable us to build designs and structures once impossible. As in biology, renewal and evolution are essential to the health of cities.

And so from the extremes of unrestrained redevelopment and sclerotic stasis, the question turns to one of how to strike the right balance in shaping a city so that it remains grounded in its past while also affording space to subsequent generations to build the future. While all sorts of specific criteria and metrics could be proposed to evaluate when a new development merited displacing its predecessor, these should ultimately summarize to the question of whether or not the lives of subsequent generations are bettered by the change.

It was the evaluation of that question that led this proposal to include the relocation or reconstruction of the IHoJ. The IHoJ’s current location at the center of the southern end of the Roppongi 5-chome West site effectively precludes any development of size on this end of the site. While that in-and-of-itself is not a problem, when considering the floor area of office space, housing, and community institutions that the site has the potential to support, the remaining options would be to build a tower of unparalleled height and expense on the site’s northern half or to otherwise cluster several towers across the middle and northern portions of the site. The latter option, while more feasible, would have the unfortunate effect of preventing many of the features highlighted in this plan, such as the large central garden, while also blocking views of Tokyo Tower from Roppongi Hills and generally creating a more claustrophobic neighborhood, with many of the windows of buildings opening out only onto the windows of neighboring buildings.

Instead of such an approach wherein the public realm would be relegated to an afterthought placed in the space remaining after the cluster buildings are constructed, the approach of forming the site around a central garden with the floor area concentrated in towers at either end allows the site’s true potential to be realized. While the existing garden of the IHoJ is certainly beautiful, as a private garden, that benefit is necessarily limited. However, through the relocation of the IHoJ and its garden illustrated in this proposal, a private garden of similar scale can be maintained while also enabling the creation of a substantial new public garden whose benefit can be enjoyed by all.

In seeking to find the balance between preservation and renewal, I am struck by a practice of Ise Grand Shrine in Mie Prefecture. Despite a history measured in centuries (if not millennia), the main buildings and bridge remain quite young, owing to a tradition of being rebuilt in alternating locations every 20 years. The hope of this proposal is that perhaps in a similar way, the IHoJ can find renewal and longevity via a similar rebuilding or relocation that unlocks its neighborhood’s full potential for generations to come.