“JAPANESE PEOPLE DON’T CARE about resale value,” says the architect Sou Fujimoto, explaining why clients have allowed him to create houses that lack conventional versions of walls, ceilings or floors, and which require the skill of an acrobat to comfortably inhabit.  Fujimoto, 43, is standing in front of House NA, a jungle gym of white steel bars amid beige apartment buildings on a quiet street in Tokyo. Built on a tiny site of just about 600 square feet, it nonetheless incorporates 21 levels connected by angled ladders, with wooden boxes doubling as step stools. Gauzy white curtains provide privacy, but not a lot; the house is as much terrarium as shelter. The owners, a husband and wife drawn to unusual designs, “bought a small lot but got a lot of living space,” says Fujimoto. Those stairway substitutes would be illegal in most countries, but in Japan, there is little building-code enforcement within private homes, which gives Fujimoto the freedom to follow through on his sometimes confounding ideas.  Fujimoto’s goal isn’t just to make spaces—the basic function of architecture—but to make people relate to spaces in new ways. Watching the couple move around the house, approaching everyday activities with the finesse the unusual design requires, suggests he is well on his way to achieving it.  He concedes that his clients have accepted “some really extreme solutions” to their housing needs. But rather than make their lives difficult, he says, he hopes to bring people “some comfort that is yet unknown.” That comfort may derive in part from landscape elements that Fujimoto blends into his buildings. During a tour of his studio in Tokyo’s Shinjuku neighborhood, the architect points to dozens of model houses with tiny trees breaking through walls, floors and ceilings. In Fujimoto’s hands, nature sometimes overpowers the built environment, a vision that could be apocalyptic were it not for his highly refined aesthetic. “I call it primitive future,” he says of the natural-artificial mash-up he is pioneering.  This fall, one Fujimoto building will help draw attention to Miami’s Design District during Art Basel, while another, in one of Tokyo’s main shopping districts, will compete with dazzling structures by the likes of Toyo Ito and Herzog & de Meuron. In California, Ronald C. Nelson, the executive director of the Long Beach Museum of Art, has been working with Fujimoto on ways to give the museum, in what was once a Craftsman-style house, new visibility. “We want a signature piece that says, ‘Oh, my God, I’ve got to go over there,’ ” says Nelson, explaining his choice of Fujimoto.  In architecture schools around the world, Fujimoto’s disregard for the expected has made him something of a hero. And he has become a constant presence on the lecture circuit, speaking in somewhat broken English but showing images that are more confident than his quiet demeanor suggests.  About half of Fujimoto’s active projects are abroad, as far away as Chile, Greece, Spain and China. But the best known of his buildings are the Japanese houses, designed to challenge clients rather than coddle them. With their odd proportions and lack of orthodox enclosure, they don’t so much restrict movement, in Fujimoto’s view, as create opportunities to explore “more possibilities” for daily life. Some of his admirers see the houses as explorations into how people will live in the not-too-distant future, when space and privacy are scarce.  For every critic who views the houses as important architectural experiments, there are many more who simply love Fujimoto’s aesthetic. The lightness of his structures can be particularly compelling. The German critic Niklas Maak described Fujimoto’s House NA as “a built optical illusion,” adding, “You would be forgiven for thinking gravity has ceased to exert its pull.”  In Los Angeles, lawyer Dana Taschner was looking for an architect to design a retreat on a tricky (if spectacular) lot on Mulholland Drive, overlooking the Hollywood sign. And who better for a tricky lot than Fujimoto? Says Taschner, “More than just knowing how to approach difficulty, which he does all the time, Sou thinks out of the box to create mind-bending concepts.” The house the architect came up with—a kind of tunnel cutting through the ridge, with views in two directions, one through a glass swimming pool that serves as a watery lens—is brilliant, says Taschner, who hopes to show it to a design review board in November.  In Miami, the developer Craig Robins tapped Fujimoto to help relaunch his Design District as an upscale fashion destination. Fujimoto’s contribution, on one of the district’s most prominent sites, is a building for several high-end jewelers, with a facade of blue glass that Robins says resembles falling water. “I’m totally thrilled,” says Robins, who chose Fujimoto for the high-profile project because he is “likely to grow in importance over time”—a prediction he is qualified to make, considering that he gave Zaha Hadid a Design District commission in 2005. Like Fujimoto’s designs, the Iraqi-British architect’s ideas were once considered too difficult to turn into actual buildings. Now she has more than 40 projects in the works.  By contrast, Fujimoto has about a dozen active projects. In Tokyo, he is completing a mixed-use building in Omotesando, the world-class shopping district that is also a proving ground for architects, including several Pritzker Prize winners. The most famous Omotesando building may be Herzog & de Meuron’s Prada store, with its vertical moss garden and bubble windows. Not far away is Tod’s, by Toyo Ito, with a flat concrete facade that suggests the branches of a tree. The Christian Dior boutique, by the Tokyo firm SANAA, is an ethereal, translucent jewel box.  Even in such company, Fujimoto’s entry is likely to make a splash. The four-story building steps back from the street at several points, and each time it does part of the structure sprouts small trees, as if the building itself were lifting a forest into the sky—a kind of Escher print in which beams become trees become beams, in three dimensions.  The building is the latest step in Fujimoto’s goal to harmonize nature and architecture. He is intent on bringing nature itself, not images of nature, into the built environment. He achieves that by either making his buildings so minimal that existing natural elements still dominate or by making the buildings veritable planters, as in his Omotesando design.  On the campus of Musashino Art University, he surrounded his 65,000-square-foot library with columns of dark-stained timber behind glass. They are deliberately reflective, making it hard to tell where the trees end and the building begins. Inside, instead of walls, the building is composed of bookshelves reaching up to the ceiling, an endless grid that becomes its own kind of forest, with the verticals as tree trunks and the horizontals as branches.  With these gestures, he is attempting, he says, to merge the forest of his childhood, in rural Hokkaido, with the forest of his adulthood: the man-made thickets of 21st-century cities. “The complexity and richness of the forest, where I grew up, is a very big starting point for me,” he says. “Now I’m based in Tokyo, and Tokyo itself is like a forest—an organic order in an artificial situation.”  “Both spaces are formed by accumulations of big and small elements,” he says. “Realizing this, I came to believe that we must be able to move back and forth more freely between architecture and nature. And thus I started the quest to create a new living environment, which would be neither architecture nor nature but the integration of both.”  FUJIMOTO DIDN’T ALWAYS plan to be an architect, though he remembers being fascinated by the work of Antoni Gaudí as a child. During high school, he regarded Albert Einstein as the greatest mind of the 20th century. He enrolled at the University of Tokyo, planning to study physics, before deciding, he says, “that my brain was not powerful enough.” Believing that the great modernist architects—including Mies van der Rohe and Le Corbusier —were as innovative as any scientist, he decided to follow in their footsteps.  Still, after graduating with a degree in architecture, Fujimoto avoided the usual path of working for an established firm. He was afraid, he says, that his ideas would become watered down. “For five or six years, I was nothing,” he says flatly. His big break came when his father, a psychiatrist and hospital director, helped him win an important commission: a children’s psychiatric rehabilitation center, which he designed as a cluster of white cubes. It attracted media attention, giving his nascent career a boost.  It is a career that has yet to pay off, monetarily. Fujimoto and his wife, Yumiko, live modestly (she works as his office manager). He rented a tuxedo for their backyard wedding in 2009, he says, and hasn’t worn one since. Most days, he arrives at his office in jeans and a T-shirt, in stark contrast to older Japanese architects, who can be stiffly formal. Fujimoto’s only indulgence is a pair of metal-framed glasses from the Japanese brand 999.9, the same kind worn by Ito, whom he describes as “the first architect who actually found some talent in me” and as “a father figure.”  The office itself, a former workers’ dormitory on the top floor of a printing plant, is almost shabby. (The work space is on six, but the building’s elevator stops at five. Fujimoto isn’t complaining—after all, his own buildings ask far more of their users than to walk up a flight of stairs.) His two dozen or so full-time employees are joined by almost the same number of “open-desk interns”—architecture students or recent graduates from all over the world, drawn to Tokyo by Fujimoto’s reputation. They work 14 or more hours a day, often building one Styrofoam model after another, like sorcerer’s apprentices trying to keep up with a flood of ideas. The practice of using interns, who generally aren’t paid, is controversial in the architecture world, but Fujimoto says that it benefits both architects and students. Certainly, it helps him stay afloat.  If his employees work in close quarters, that doesn’t bother Fujimoto, whose work is often about doing more with less—about, as he puts it, fitting architecture to the human body. Toshiko Mori, a New York architect and the former chair of the architecture program at the Harvard Graduate School of Design, says Fujimoto has a gift for devising structures that “create small moments of connection.”  That was nowhere more evident than in the pavilion he designed for London’s Serpentine Galleries in 2013. Each year, the gallery commissions an architect to create an event space in Hyde Park. (Fujimoto is the youngest architect to receive the prestigious commission, which has been awarded to Frank Gehry, Rem Koolhaas and Hadid.) His novel design wove thousands of steel bars into a kind of high-tech hedge. Transparent disks, set on the bars at various levels, became steps, tables and chairs. It allowed visitors to shape their own experiences, at different levels, the way children might choose different perches on a tree. At the same time, the pixelated structure blurred the boundary between indoors and out.  When Fujimoto has an idea, he may use it more than once. In fact, he is hoping to build a 1,000-foot tower in Taichung, Taiwan, that bears a strong resemblance to his Serpentine Pavilion. The Taichung government hopes the scaled-up version will become a symbol of that city—a kind of cloudlike Eiffel Tower.  During an interview last year, the Japanese architecture writer Yoshio Futagawa kidded him about the practice. “I sometimes find you taking models from other projects and simply scaling them up for reuse,” Futagawa said. Unfazed, Fujimoto responded that he wasn’t plagiarizing. Rather, he said, “It’s like growing crops—watching the seeds transform through generations. I sift through them, picking up the ones that look interesting and throwing away those that are no good.”  The seeds go back to one of his first projects in Tokyo, a six-unit apartment building that appears to be a pile of houses, stacked irregularly in a nod to the chaotic urban environment. The contrast between the traditional elements—the building components look like Monopoly houses—and their untraditional use made photographers swoon. The project also established his reputation for using conventional elements in unconventional ways.  Another early effort was the Final Wooden House, consisting of thick blocks of cedar stacked and staggered to create what might be called a rectilinear cave. It was as dark as House NA is light, as earthbound as the latter is airy.  Somewhere between those two extremes, but no less pioneering, is House N, consisting of a box within a box within a box—three enclosures, each with large windows, cleverly offset to allow privacy. Fujimoto says the boxes compel playful engagement with the architecture. For example, he says, there is a typical bedroom, but there are also many other places to sleep, depending on your mood and on the weather.  Japanese dwellings have historically been flexible, with little furniture other than tatami mats, and shoji screen partitions to allow rooms to take on multiple configurations. When the West was building marble and gold-leaf edifices like Versailles, the Japanese were building paper palaces. By designing houses with sliding walls and interlocking spaces, Fujimoto isn’t defying Japanese tradition but reinventing it.  Even with the international acclaim his Serpentine Pavilion brought him, the self-effacing architect is still a novice at winning clients’ confidence. Last year, the owner of an estate in Connecticut asked him to come up with ideas for a pool house. Fujimoto sent two sketches, both of which the client nixed. Next time, he says, he would insist on a face-to-face meeting, where he could explain—and offer to modify—his proposals. Providing ideas free of charge, as he did for the Connecticut client, is hardly a sustainable business model. And he got paid “almost nothing” for designing the Serpentine Pavilion, though the gallery sold Fujimoto’s pavilion to the billionaire pharmaceutical heir Maja Hoffmann for an undisclosed sum.  Whether they’re lucrative or not, Fujimoto is attacking commissions with almost ferocious creativity. In his office, scale models of planned buildings are everywhere. While some of the concepts will never be realized, Fujimoto says, “the thoughts are there in your mind to enrich ideas in the future.” Besides, he adds, with everything that could go wrong, any completed project “must be the result of miracles.”  There’s no way to know yet how many miracles will occur, but if Fujimoto wanted to, he could charge admission to his impromptu “model museum.” There, on the sixth floor of a nondescript building, visitors would get a glimpse of architecture’s bold, primitive future.
Fujimoto’s designs eschew the predictable and often force viewers to relate to space in a new way, making the Tokyo-based architect a hero in his field.