The architecture of Kazuyo Sejima, Ryue Nishizawa, and their joint office, SANAA, has an enigmatic quality. Forms float ephemerally within everyday surroundings, creating juxtapositions between buildings and context that provoke our surprise and interest. As is evident from the long and successful career of these three collaborative offices, appreciation of their designs has grown to a global level. Fortunately this huge expansion in scale and accommodation of a broad range of building programs has not altered the simplicity and clarity of their approach, which is to heighten a sense of mystery in terms of how a building inhabits its surroundings. This is apparent in their current exhibition at TOTO Gallery Ma in Tokyo, Kazuyo Sejima + Ryue Nishizawa / SANAA: Architecture & Environment, in which they explore the boundaries between building and landscape, challenging our notion of this separation through designs that blur distinctions and focus on integration. The projects in the exhibition represent exploration and collaboration among the three different offices of SANAA, Kazuyo Sejima & Associates, and Office of Ryue Nishizawa.

Projects such as the New Kagawa Prefectural Gymnasium provide insight into the way in which Sejima and Nishizawa explore the relationship between architecture and the environment. Situated on a redevelopment site facing the bay in Takamatsu City, the entire building is covered by an undulating roof that evokes the image of a natural landscape. Imagined as a floating island on the Seto Inland Sea, the building subtly recognizes its location in simplicity of form―but in keeping with SANAA's passion to focus on space-making as opposed to object-making, it acts as a porous space that absorbs activity and creates links between the arena functions, park, and nearby station. Attention to all levels of scale is evident, as various models on exhibit convey the roof concept, overall interior, and structural details.

The O-Project is a hotel complex on an expansive rural site in Europe that articulates complex spaces with simple repetitive arc-shaped concrete roofs. While the form is fresh and unique in its design, there is a consistency in its exploration of the architecture-environment relationship. The clarity of one all-encompassing roof is so strong that the presence of an exterior and interior boundary is blurred into a singular integrated space. While the concrete shell is deceptively thin at a 150-mm depth, the structurally ideal circular form allows for huge spans that float ever so lightly upon four columns at each corner. The arc roofs offer flexibility so that small interior rooms as well as extensive terrace spaces can be planned and arranged.

The Puyuan Design and Event Center in China is also an experimental exploration of scale that questions separation between architecture and its environment. The site is a small island set within the river system of the town. As opposed to locating a building "on" this site, Sejima proposes to enclose the entire island in a glass dome, thereby blurring boundaries in an "architecturalized" landscape. While the dome is a large-scale structure covering a huge space, the construction itself is a play on scale where large structural beams or columns are absent. The entire roof is a rigid mesh of stainless-steel tubes with an average diameter no greater than 30 mm, suitable for assembly by human hands. The result is not a building, but an environment that interweaves built structure with river, trees, and sky.

While most architectural exhibitions tend to present buildings as physical objects, this show invites you to perceive space in new ways through the relationship with its context. Natural surroundings, climate, human interactions, and culture are treated as architectural elements that create an interwoven fabric of elements, continuing to pique our interest and urge us to question the conventional boundaries between architecture and environment.