When the 21st Century Museum of Contemporary Art opened in Kanazawa in 2004, anyone arriving from any direction met a wall of glass. The museum is a circle about 113 metres in diameter, low, transparent, crossed by corridors that can be entered from every side. There is no monumental entrance, no hierarchy between front and back, and from outside you see people moving between the galleries as in an aquarium. The project won the Golden Lion at the Venice Biennale that same year. It is signed by Kazuyo Sejima (b. 1956) and Ryue Nishizawa (b. 1966): SANAA.
Sejima trained in the studio of Toyo Ito, and shares his attention to a light architecture, conceived as an interface between people and environment. She founded her own studio in 1987; Nishizawa, ten years younger, joined as a collaborator, and in 1995 the two founded SANAA (Sejima and Nishizawa and Associates). Nishizawa also continues to sign projects of his own, such as the Moriyama House in Tokyo. In 2010 they received the Pritzker Prize together.
The beginnings: living in a row
Before the museums, Sejima made her name with residential buildings in which the plan grows directly out of a way of living. In a pharmaceutical company's women's dormitory in Kumamoto (1991), the bedrooms are gathered into compact blocks and the rest of the building is a large full-height common space where the employees study, eat and meet: the private part is reduced to a minimum, the shared part is the real home. In the Gifu Kitagata social housing (completed in 2000), Sejima designed a long, extremely thin building, only one room deep, in which each apartment is a sequence of side-by-side rooms linked by an external corridor and punctuated by double-height terraces. Seen from afar the building looks like a perforated wall; from inside, every room receives light and air from two sides.
These projects already show the idea that runs through all of SANAA's work: the building as a diagram of the relationships between people, without formal hierarchies imposed from outside. One room is not more important than another because it is larger or more decorated, but because it hosts a shared activity. It is a way of thinking with social roots before aesthetic ones, and it explains why the practice has always regarded its buildings as unfinished until they are used.
The method: a hundred models to remove one element
The image is one of lightness; the method is one of dogged persistence. For each project the studio produces hundreds of scale study models: not to refine a form, but to test whether a column, a wall, a thickness can be eliminated without the whole collapsing. The columns are extremely slender steel tubes, often only a few centimetres in diameter, which at Kanazawa hold up the roof and at Essen hold up the floors. The slabs are thin. The glass walls have almost invisible mullions. What remains is the structure reduced to the necessary minimum, and this minimum is studied with the same precision with which other studios draw ornament.
Three envelopes, three answers
The Zollverein School in Essen (2006) disproves the idea that SANAA works only with glass. It is a concrete cube about 35 metres on each side, built within the decommissioned Zollverein mining complex, a UNESCO World Heritage site. The walls are pierced by more than a hundred square openings in four different sizes, arranged not on a grid but according to the needs of the interior spaces. The most interesting technical choice, however, is invisible: the concrete walls are about 25 centimetres thick and have no conventional insulating layer. Inside them run pipes carrying warm water pumped from the mine, which has to be extracted from underground anyway to prevent flooding. That water, at around 27–29 °C, warms the walls and acts as "active" insulation: a local resource that would otherwise be wasted replaces an insulating material.
The New Museum in New York (2007), on the Bowery, tackles a different problem: a narrow lot on a dense street, where a transparent building would make no sense. SANAA stacks seven boxes of different heights, shifting each slightly relative to the next. The offsets between the boxes create skylights that bring daylight into the galleries and outdoor terraces, and allow column-free rooms. Everything is clad in expanded aluminium mesh mounted over corrugated panels, which makes the volume opaque yet vibrant, changing with the daylight. The third envelope, the glass of Kanazawa and Toledo, completes the picture: SANAA has no favourite material, it has a way of asking how much a building should reveal of itself.
A slab that undulates: the Rolex Learning Center
In 2010 SANAA completed in Lausanne, on the EPFL campus, the Rolex Learning Center: a library, a study space, a service centre for students. It has no superimposed floors. It is a single concrete slab of about 120 by 160 metres that rises and falls in gentle hills, with circular patios open to the sky, and beneath it a continuous space with no doors and no dividing walls. To build it, the slab was cast in place on curved formwork calculated to the millimetre. The result is a building in which changing level means walking uphill, as on a slope. The library is a landscape.
The idea is that a space with no internal boundaries produces different behaviours: students sit on the slopes, work in groups where needed, move around without crossing thresholds. Not all users are convinced: without walls noise travels, and the curves make furnishing difficult. SANAA accepts the price, as always, in the name of a principle: a public space must be crossable by anyone, in any direction.
Teshima: a drop of water under a shell
The project that pushes this research furthest is signed by Nishizawa alone, with the artist Rei Naito: the Teshima Art Museum (2010), on a small island in Japan's Seto Inland Sea. It is a concrete shell about 40 by 60 metres, at most a little over four metres high and just 25 centimetres thick, without a single internal column. Two large oval openings in the roof let in air, light, rain and the sounds of the surrounding hillside. On the floor, droplets of water emerge from tiny holes, run slowly across the surface, merge and form small pools that change shape throughout the day. The shell was built by pouring concrete over a precisely shaped mound of earth, which was then dug out once the structure had hardened. There is almost nothing to look at, yet visitors sit on the floor for tens of minutes: it is perhaps the purest example of an architecture that steps out of the way to make room for experience.
In the United States, at Grace Farms in Connecticut (2015), SANAA applied the same idea to the landscape: a single thin, sinuous roof, more than four hundred metres long, runs down a grassy slope like a river and covers, along its course, a meeting hall, a library, a children's space and a covered court. Between one volume and the next the roof floats above open spaces, and the boundary between inside and outside becomes uncertain. In 2010, the same year as the Pritzker, Sejima also became the first woman to direct the Venice Architecture Biennale, with an exhibition entitled People meet in architecture: a title that sums up the practice's entire body of work well.
The Louvre in a coalfield
The Louvre-Lens (2012) adds a political meaning to SANAA's language. The French State decided to open a branch of the Louvre outside Paris, and chose Lens, in the north of the country, an area marked by the closure of its coal mines and high unemployment. The museum stands on the site of a former mine shaft, and SANAA designed it as a series of low, elongated volumes clad in glass and polished anodised aluminium, resting on the ground and slightly rotated relative to one another to follow its contours. Its heart is the Galerie du Temps, a hall about 120 metres long with no partitions, in which works spanning five thousand years of history are arranged chronologically along a single route: visitors take in the whole sequence at a glance instead of walking through one room after another. Even the reserves, the stores where works not on display are kept, are partly visible to the public. It is SANAA's transparency applied not only to materials but to the institution itself: showing how a museum works, as well as what it exhibits, in a place that had until then been left out of the geography of high culture.
The limit of transparency
The most frequent criticism is that SANAA's architecture is more beautiful to photograph than to inhabit. Glass heats up in summer, smooth surfaces hold nothing, the absence of detail makes the buildings mute and, when they are used intensely, a little inhospitable. SANAA's implicit answer is that the architect's task is not to fill space but to prepare it: it is up to those who use it to give it character. It is a position consistent with the Japanese tradition of the void, the ma, and it has a practical consequence: SANAA's best buildings are those in which use is intense, and the void is filled by real activity. The busiest museums work better than the deserted ones.
What it teaches designers
Behind the apparent simplicity of SANAA's buildings lie technical problems that every designer meets as soon as they try to imitate them. A steel column only a few centimetres across has to be protected against fire, often with intumescent paints that swell with heat and must be planned from the outset so as not to thicken the section. A very thin slab deflects more under load, and the glass walls resting on it must tolerate those movements. A continuous slab like the one at Lausanne means solving problems of acoustics, services and fire escape within a single element. SANAA's lesson is not that these problems disappear, but that they must be solved within the design rather than hidden above suspended ceilings and behind cladding. It is a way of working that requires close dialogue with engineers from the very first sketch: lightness, in architecture, is always the result of a calculation.