Had the Mori Building Company the power to summon the dark arts to create an architect from the ether, one who would embody in practice and sensibility the far-reaching, life-affirming, Earth-sustaining vision — the “Vertical Garden City” — of its former president Mori Minoru, it might take precisely the form of architect Christoph Ingenhoven. But despite having had fortune smile upon his career at key points, it was anything but magic that took him into global view. In fact it was a struggle from the midst of boisterous contrasts.

TEXT BY DAVID G. IMBER
Photo ©Ingenhoven Associates
Photo(Top) ©ingenhoven associates / HGEsch
EDIT BY KAZUMI YAMAMOTO
illustration by Adrian Johnson

“Just today I did a quick calculation of how large the world’s population will be in 2050 and what the average life expectancy will be,” Christoph Ingenhoven explained. “Then we factored in not only how many elders there will be but how many will be living in cities. In 2050 we will have 1.6 times more life-years that will be spent in cities like today’s. That’s an enormous amount of work that we have to do in the next 25 years.” At times the architect sounds like this; like one who earned his degree from RWTH Aachen University, lauded globally for the surpassing excellence of its technical curriculum.

At other times something else emerges that reflects the middle years of his education, which he spent at the Kunstakademie Düsseldorf under the tutelage of Pritzker laureates Hans Hollein and James Stirling; “the peak of postmodern education in Germany!” the architect wryly proclaims. He explains that in 1978 and the years following, postmodernism occupied every part of German university life. It was a jarring turn from his education at Aachen, where engineering was held in the highest esteem, yet simultaneously the practice suffered from being seen as subjugated to the design intentions of the architect as artist.

But the student Ingenhoven had a leg up on his classmates, having worked for his father’s architecture office in Düsseldorf from adolescence. For as long as a decade before he set foot in university he’d spent countless hours visiting sites and drafting in a working architecture office. He was already conversant in the basics, and felt ready to compose with them. Aachen was, in his words, a “very technically-oriented university. A lot of mechanical engineering, chemistry, physics, car design, track design, train and aircraft design. Architecture is sort of the ‘one special thing’ they offer.” He felt himself, “a little bit… exotic.”

Representing a peak in Ingenhoven’s architectural explorations, the road to Kö-Bogen II took many turns.

Aachen, in the late 70s, taught the modern classical canon: Mies van der Rohe, Walter Gropius, Le Corbusier while, as Ingenhoven describes it, European universities were being flooded with postmodernism, and in addition to Hollein, architects like Stanley Tigerman and Denise Scott Brown had entered academia. He wanted to be part of this group that he says “taught us about the meaning of architecture and the meaning of façades and order, and many things that had been blocked out by the over-rational and very commercial kind of modernism” that typified the Germany he grew up in.

At the same time, another great wave of activism arose in Europe. In 1981 members of the Green Party began taking seats in the German parliament. “It was a very big thing … an antiwar, pacifist movement which, at the same time was about health issues and how to live a healthy life.” And of course the Greens were the first political party to commit to the idea that the health of the planet itself was in jeopardy, pointing out the potential for nuclear catastrophe in the short term, and the specter of depleted resources and climate change in the longer term, tipping the ecological balance toward extinction.

He resumed study at Aachen to acquire his architecture degree, and it was during the ensuing period, while fulfilling his required term of public service, that fortune intervened to combine with what was either youthful ingenuousness or supreme self-confidence. A former classmate called, out of the blue, to urge Ingenhoven to enter a competition being held by Deutsche Post, at the time a colossal state-owned conglomerate, for new headquarters in Cologne. The friend had somehow been able to persuade the company that they should bestow a “wild card” spot to an anonymous entrant. “I didn’t even have a license as an architect. I had no staff, no office, nothing. I was just a student doing civil service at the time.” (He laughs boldly about it now.) “I didn’t even have a car, I had nothing.” He dusted off space in his father’s office, hastily hired two ex-classmates, and won the competition. It should be noted that five other entrants were prominent German firms, including a Pritzker Prize recipient, Gottfried Böhm.

It wasn’t built, nor were many of his succeeding designs, despite winning their respective competitions. But the experience sent his eye farther afield, to builders like Renzo Piano and Richard Rogers, whose Centre Pompidou embraced neither the historicism and decorative formality of postmodernism nor the hyperrationality and commodification of the later modernist architecture it was distancing itself from. “You didn’t know what the real ‘new thing’ was, … there were some people who were not as heavily influenced by postmodernism, especially Piano and Rogers. Engineering combined with architecture. It wasn’t just about form-giving and decoration and beautiful drawing. It was about big, real, new things.”

The architect looks upon this period of competing, though not building, with characteristic positivity. Of that odd, adventitious early win, he says “it was already a project with atriums, with a winter garden; there was a double-skin façade. There was a lot of thinking in this very early project that later on was part of our architecture career, and it was done to what was then the maximum reachable level of ‘green architecture’. It was fresh, it was new, and very contemporary.”

Much of the architect’s early work won competitions but went unbuilt. The Commerzbank AG Headquarters provided a greater reward in the opportunity to work with Frei Otto. © ingenhoven associates

The architect’s avid competition era culminated a few years later with two triumphs in a single week. One of the two winning designs, the Commerzbank AG Headquarters, Frankfurt am Main, was never built, but would inscribe a lasting chapter in his career. “I was looking for somebody who could be the advisor, the teacher that, in a way, I never had.” As the scientific method may involve the examination of extreme conditions to find the mean, Christoph Ingenhoven’s practice had come to a point where he sought guidance from a teacher of like mind who’d blazed further along the path. Frei Otto, “whose world and life was about building more with less,” as Ingenhoven aptly represents it, was that guide. And here again boldness or audacity, or simply trust and meaningful determination served the architect well. He just located the master’s phone number and called him. Perhaps surprisingly, Otto agreed to work together. “He was a friendly man, but he was very strict,” a quality Ingenhoven found made him easier to work alongside because of his readiness to assume the role of the stern and exacting teacher, which at that moment the architect felt at home with.

The other winning entry of that momentous week was, in fact, the Ingenhoven office’s inaugural built structure, and it emerged as a work of ideas in full flower.

The RWE Tower in Essen was the office’s first built work, and the highly advanced technology on display serves as a rubric to the body of work that followed. © ingenhoven associates / HGEsch

At 127 meters, the RWE Essen tower is considered Germany’s first ecologically-oriented high-rise. RWE needed to get out in front of its image as an energy conglomerate by expressing its awareness of environmental concerns. The building is a technological masterpiece that allows workers to control all aspects of the internal environment while expending far fewer resources overall. “It was the first building ever on that scale built with a double-skin façade, a naturally-ventilated skyscraper. And from then on there were thousands of buildings around the world built with double-skin facades.” For it, the architect developed a novel mechanism for controlling light and ventilation within the twin-shell glass façade. So-called “fish-mouth” ports on every other landing offer maximal light penetration, cross convection that automatically adjusts to climatic changes in wind and air pressure, and give users the ability to control all functions according to individual needs by means of an interior control panel in each space. In addition to pulling plant life up into the building’s interior, the structure’s tight, circular plan also allowed the architect to pull it back from the grid’s edges to deliver the first of many park spaces Ingenhoven would make a signature element of later buildings at larger scales.

It may have been here that the set of principles the architect calls supergreen, the abiding philosophy that has suffused all of his work since, began to take root. Ingenhoven and his team coined and even copyrighted the term. It involves going far beyond the standard in lessening environmental impact to adding like value, whether that be by incorporating a discrete green respite from urban congestion, moving toward negative energy expense or, as stated in the firm’s own precis, “to ask ourselves when building: What’s going on with spatial psychology?” To work from a foundational notion of how people feel in spaces, and how to promote feeling good, feeling safe, enhancing health. Supergreen compels the architect, on every venture out, to explore the possibility of using built structures for healing on the personal, community, and global level in a way that transcends style statements. The architect adds, “There is no one convention, no one typology … the best of all architecture has always been dedicated to humans, their beliefs, their needs and their ‘good life’”.

The concept of joining disparate locations to form a stronger, more life-supportive whole runs through all of Christoph Ingenhoven’s contemporary work, and it is of a piece with the supergreen philosophy. “It’s about connections. If you build something, you take away something,” says Ingenhoven, “you take away a part of the city or the landscape. And you know, to be honest,” here he laughs at the measure of his understatement, “we shouldn’t do that too often anymore. And if we do, we have to care for giving back as much as possible. If you compare three projects from the office over the past ten years, Toranomon, Marina One in Singapore, and Pier One, they’re all driven by the same search for giving back.”

Pier One revivified a port district of Düsseldorf by connecting its disparate features. If all visitors can recall of the structure is “four bridges” the architect is fully on board with that. © ingenhoven associates

In the case of Pier One, he returns to his hometown of Düsseldorf something it lost to progress. Some of the town’s harbor is still used as it once was for seabound trade. But much of it was converted to commercial space and office space, with a smattering of residential. The architect was presented with a panoply of problems in trying to revivify its use and generate the revenue required to justify the cost of building. For one thing, “‘residential’ never wants ‘industry’, and vice-versa. We are in the middle of all of that.” The site presented three piers, three “peninsulas”. “If you want to get from one to another you had to run a long way,” he explains, again jovially understating the scope of the project. “In a way, it’s a very obvious idea but no one had it, to build bridges between the tips of these peninsulas and connect it all. So we’ve now built four bridges to connect three of these peninsulas. The idea for financing it was to build something that earns back some of the money that you spend on the bridges. So we developed the idea of the pier that extends the middle of these three peninsulas, which is a little shorter. If people remember this building as ‘four bridges’ that’s OK! Like I’ve always said of the Lufthansa headquarters in Frankfurt [completed 1999], if the people remember the gardens and not the architecture I’m fine with that. Because its central idea was to have ten gardens, right?” Ingenhoven then admits to something stunning from an international builder of his prominence. “The building was just the excuse for building the gardens,” and its not possible to discern whether he’s dead serious or indulging his penchant for good-natured humor, with a point.

One could be forgiven for thinking that his ideas having matured, his vision of future architecture instilled, the architect’s postmodernist mentoring at the Kunstakademie would be relegated to the reference shelf. Unmistakably contemporary in its design and the environmental exigencies it addresses, the Stuttgart Main Station, to be completed in 2025, which looks like little before it, could not possibly have taken cues from his teacher, James Stirling. The elder architect’s New National Gallery in Stuttgart “is absolutely not what I would build,” he says, yet he explains that what he sees in it is “this idea of a museum building that is not just a museum but also a place for living, for passing through, being part of the melee of movement that you have in a city like Stuttgart. My station is just across the street, so I know it pretty well.”

Due for completion in 2025, the Stuttgart Main Station, known as Stuttgart 21, simultaneously creates an entirely new, human-scaled city center by reweaving its above-ground features, and provides more efficient access to the greater European railway system below.　© ingenhoven associates / HGEsch

The enormous station, yet another of the studio’s international competition-winning projects, eliminates the existing ground-level track yards to give back to the city a substantial part of Stuttgart’s most important park, the Schlossgarten — what ingenhoven associates refers to as the city’s “green heart” — and it will provide a better connection to the entirety of the greater European railroad network. Typical of railway systems built in the 19th century, it once girded the city it served, but in the intervening years Stuttgart grew up around it, putting the terminal in the midst of dense construction. Relocating the tracks underground not only increases green space, but also returns space for a new city center. ingenhoven associates has simplified and rationalized the number of tracks and platforms, and will oversee a new tunnel perpendicular to the existing tracks to accommodate high-speed transport.

The new station hall benefits from a comfortable climate without the need for additional air conditioning, thereby reducing energy consumption related to cooling, heating, and ventilation. The design pushes against the feeling of being underground through its attention to “brightness and openness,” and will be illuminated in the day by numerous “light eyes” atop the chalice supports that allow park passers-by to view the workings of the system beneath. As a result of the studied deployment of these light inlets, the station will not become too warm in summer. In winter, the subterranean hall will be warmed by the surrounding soil as well as air currents from the tunnels. At the same time, incident daylight will reduce energy consumption from artificial lighting. Photovoltaic modules will be installed on the roof of the historic Bonatz building to generate energy during dark periods.

The biomorphic shell is a study, the architect believes, in lightening the imposition of the built on the natural. “If you look at the building site now, at the concrete, it’s not flying, it’s not weightless, but it’s as weightless as it can be.” Ingenhoven regards this as part of a general approach he takes to all of the firm’s projects. “It’s done to the point that you can’t take away any more without losing the functionality of the building. So there’s no decoration. I’m a deep believer that human-made things — buildings, cars, aircraft, seacraft — are as beautiful as they are minimized. Not a kind of artistic minimization, where you go beyond the extent where you’re making the point. It’s just taken to the point.” He cites the oft-quoted Einstein dictum to drive this home, “you should do the minimum but not less.”

Toranomon Hills Business Tower Landscape　© ingenhoven associates / HGEsch

Across the globe, Ingenhoven’s intervention in the fabric of Tokyo is no less momentous, and addresses many of the same priorities as his Stuttgart station, Pier One, Kö-Bogen II and other projects, with its ability to connect widely disparate, difficult to navigate sections of the cityscape, combining a series of natural topological gestures designed to integrate the made and natural environments; to restore them to humanistic proportions. The Toranomon business and residential towers were also a competition project, the latter being Tokyo’s tallest residential tower, at 220 meters and 54 stories. “I think Mori is the most ‘out of the box’ developer in Japan.” The Vertical Garden City philosophy that drives the company asserts that a city’s density is crucially linked to the progress of society, but that it is inhumane to impose an environment in which the security and support of community and the respite offered by access to nature are jettisoned in the process. Ingenhoven felt that what his office could offer might take the pursuit of this new view of urbanism to a next level.

From left, Toranomon Hills Business Tower, Mori Tower, Residential Tower　© ingenhoven associates / HGEsch

“Tokyo is such a fascinating city for me, because on every corner and on every hill it changes character,” Ingenhoven tells us. “It’s a village, and it’s a megacity. It’s a terrifying town and a beautiful town. It’s really everything.” He deems Tokyo, “one of the highest forms of civilization-centered construction.” Working with the mandate to connect his new structures to the massive Mori Tower they’d flank, he explained how he came to his understanding of what could be done with the site. “It’s about connections. … There was a little garden around that central tower, and I remember one sunny morning sitting there on a chair, and I was fascinated by the fact that you could sit there relatively quietly, in the sun, under the trees, and in a way you could forget you’re in a big city … I said ‘OK, if that’s possible, and if you can establish two, three or four places like that around these two towers, connected with that [nearby] hill to the shrine, you could create a relatively small but maybe very valuable public garden. … You can walk uphill to the shrine or back, from one to the other building, sit in the sun enjoying coffee or watching your child. You could say this is not a big thing, I would say it’s the biggest thing you can achieve.”

We asked him about the “colors, scents, and sounds” he refers to in his own writing on the project that are incorporated into the design to stimulate the senses. He explained, “I think the emotions and sensations that you can experience have to do with the absence of noise and distraction. So if you walk from the shrine, down the small street and on to the small bridge, then over to the residential tower, passing by the slightly raised terrace; then on to the central tower, and from there toward the business tower — it’s a bit of a journey, but you’ll get it all. You’ll hear the sounds of the city in the back, but you’ll also definitely have trees and birds. You’ll have water, you’ll hear the conversation of other people chatting.” This, for Christoph Ingenhoven, is part and parcel of supergreen futurism.

Kö-Bogen II, Düsseldorf. Environmentally groundbreaking, but just as meaningfully, it recovered a place of respite, where it enters a kind of conversation with two highly distinctive works from other eras, previously hidden beneath elevated roadways.　© ingenhoven associates / HGEsch

We came to a point in our conversation at which we felt prepared to ask about one of the most unusual and frankly startling projects we’d seen from his or most any architecture office in the past several years. It sits in the center of the architect’s hometown, an area that he’s given nearly three decades to contemplating. We learned that striking as its appearance is, Kö-Bogen II emerged quite naturally from a near storybook confluence of contrasting demands by highly distinct interests.

From an architect whose building style can be generally described as “quietly commanding”, on encountering Kö-Bogen II, the imposing incongruity of its greened face is almost intimidating. To some it may recall Fukuoka’s Acros building by Emilio Ambasz. But that building is now over a quarter-century old. It partakes of the green technology and thinking of its time, which is closer in development to the High Line in New York City, where designers imposed a certain level of control, then invited nature to effectively “throw the dice” in reintegrating it into the fabric of its surroundings.

Kö-Bogen II features the world’s largest green façade, and very much unlike a building like Acros, it is unremitting, almost dreamlike, in its appearance of precision and order. Its roof and three of its sides are outlined with eight kilometers of hornbeam hedges, over 30,000 plants in all. The hornbeam was selected because it remains green in winter, and its overall ecological benefit is considered to be equivalent to that of approximately 80 fully-grown deciduous trees. The green oasis affects the city’s microclimate. It protects against the sun’s rays, negating the urban heat island effect. The structure also collects and retains rainwater. Sealed surfaces in many urban areas interrupt the water cycle, putting strains on local sewer systems. Kö-Bogen II uses exactly as much as needed, draining off the excess and closing the gap in the water cycle. “It binds carbon dioxide, stores moisture, attenuates noise, and supports biodiversity,” the architect succinctly explains.

None of this occurred in a remotely haphazard way. Ingenhoven informs us that, “the botanical, technical side works perfectly. There hasn’t been a single plant or tree replaced so far. We looked to the ‘greening’ of the project from a very botanical perspective. We engaged two professors from Munich and Berlin to make sure that we selected the right tree and plant species, and to make sure that the nutrifying, hydration and aeration were exactly right, and how we’d maintain the greens once they were on the building. We hire a nursery or find a piece of land ourselves where we can grow things. And so two or three years before the plants go onto the building we know them already, we’ve treated them well, and we’ve maintained and prepared them to arrive at the building site. And so what is the Kö-Bogen II? It’s a statement, in a way. In many of our projects we try to stretch the boundary of something.”

But neither was this a totally uncanny occurrence of an idealistic architect imposing their will. The project satisfied the needs of retailers, who required a transparent, showcase front, but don’t need to have other open views. “The investor saw their advantage in the signature of that green building, and the aspect of ‘standing alone’. The city saw the chance to refurbish or restructure the city.” For ingenhoven associates it was a chance to create a green building on a scale they’d never before attempted.

When we returned to asking about the appearance of orderliness we came to understand that, looked at out of context, the unrelenting order seems almost feverish. As the architect explains its meaning we realize that this truly was a project thirty years in thinking. “Kö-Bogen II was also about healing the city. Everyone talks about the green façade, but for me it’s more about a city that was destroyed by the war, heavily, and also by destruction after the war that was consciously done by people who wanted to turn Düsseldorf into a kind of motorway-dominated city. And that was such a big mistake that it had to be corrected.

“It was terrible. It was a roundabout for a tram, and there were eight lanes of traffic. It was part of a trestle motorway through the city. The buildings that are there, the Dreischeibenhaus, the high-rise, and the Schauspielhaus, the theatre building, were isolated somewhere behind the traffic. And the Hofgarten,” Düsseldorf’s “green necklace”, “was disconnected, there were cuts throughout the garden for the motorway. So the whole concept we developed 29 years ago was about healing that situation, reorganizing the urban structure so that it makes sense again, so that it is enjoyable again. If I’m proud of one thing there… Well of course there’s the green façade, but that’s not the main thing. The main thing is that people enjoy walking there with no need to spend money, with no pure commerce. If they can just sit on the piazza and watch their child play, or come out of the theatre and sit and think, that’s the best thing that can happen.”

And the insistent orderliness, again, is not simply stylistic. “I saw that building as part of the Hofgarten. I see the back of this building as part of the park, and the park is kind of an English garden, but with French elements. So we strove to make it a continuation of that park, in perception, and not a building with other buildings. If you walk around there it’s pretty free, unconventional and unexpected.”

We’d asked another question in quest of some enduring sense of what bound Christof Ingenhoven’s architecture intellectually and aesthetically, and immediately regretted its frivolousness. We asked, blankly, whom he’d like to converse with, living or dead. His answer, however, was immediate: “Buckminster Fuller would be one. I never had any opportunity to meet him. I met Frei Otto of course, who was, perhaps, of similar mind in a European context.” But among architects his affinities were drawn more clearly. He spoke of Glenn Murcutt, whose pursuit of built structures that touch the Earth lightly are so consonant with his own perspective, as well as Albert Frey, whose work imparted a lexicon to the Palm Springs milieu. “I’m very interested in people who have that kind of careful approach to what they do. It’s unusual,” he allows, with a gentle laugh.

As we were closing the conversation the architect turned to talking about New York City, which he’d at some point described in terms of offering, “the possibility of living with the complete lack of human scale or human habitat.” Prepared for the worst, we were instead met with words of encouragement, the fitting end to a generous and open talk, and perhaps a key to Christoph Ingenhoven’s work that we’d sought from the first.

“I’m what you might call a follower of gardens and nature. I’m depending on that. You can live without it, but when you experience it you recognize that this is your environment, your habitat, and if you get too far from it, it’s very difficult. But in New York there’s Central Park, which was a wonderful, wonderful idea 200 years ago. What a great strategic decision! Those people had such a long view into the future, and it was so successful. We should feel a little small compared to that kind of decision. To be able to make big, long, strategic decisions for cities, to make them beautiful for the next 200 years, and position them in the right way… It could be easy, because we all know what to do,” and characteristically, he laughs. “So it’s time to ask the responsible people to do what they so obviously must.”

Christoph Ingenhoven
Born in Düsseldorf, Germany, 1960. Took time as an undergraduate at RWTH Aachen University, from which he received his degree, to pursue study at the Kunstakademie Düsseldorf under Hans Hollein. He has directed Ingenhoven Associates, recipients of numerous international awards, since 1985 and has been focused on ecological and sustainable design from its foundation. © Jim Rakete

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