Sejima and Nishizawa received the 2025 RIBA Royal Gold Medal for architecture at 66 Portland Place last week, with RIBA president Muyiwa Oki presenting the ceremonial medal. SANAA won for ‘both functional and profoundly elegant [buildings], offering a sense of calm amidst an increasingly complex and chaotic world', as well as ‘sustainable, user-centred design’, the RIBA said. The practice’s work at home and abroad includes art galleries such as the New Museum of Contemporary Art in New York, the 21st Century Museum of Contemporary Art in Kanazawa (2004), Louvre-Lens in France (2012) and the Sydney Modern in New South Wales, Australia (2022).Advertisement The AJ sat down with Sejima and Nishizawa before the ceremonies to discuss what makes Japanese architecture different, the Osaka Expo, and the beauty of the RIBA’s toilets. It’s the first time in nearly 20 years that a Japanese architect has won the Royal Gold Medal. Is Japanese architecture having a moment? One of the reasons for this is that we have very wet humidity; we have typhoons. This forces us to use very light walls. So architecture in Japan becomes a box. It becomes visual. It’s a little bit flexible. Japanese architecture also looks different from architecture in other regions. It is really different from Chinese architecture, for example. Japanese architecture is reactive to the natural environment. ‘Japanese architecture is reactive to the natural environment’ In Japanese architecture, we don’t see the diagonal glazing you have in Europe, because once you put diagonal [bracing], the frame becomes stiff. We always try to be dynamic.Advertisement Are architects less important now – arguably at a time when they are needed most? Nishizawa: I hope architects stay important, but the meaning of ‘architect’ can be different. We have some special techniques [for] placemaking. I believe this is still important for human society. And I think the meaning of ‘architect’ can be changed. For instance, there will be a new architecture created by group collaboration, not only traditional architecture, but also the people living inside (co-design). ‘The meaning of “architect” cannot stay within the traditional definition’ The meaning of ‘architect’ cannot stay within the traditional definition of ‘architect’, but still, there must be somebody who can use special techniques to create space for people. Does minimalism mean fewer materials? And what about architecture’s return to ornamentation? Nishizawa: We are minimalists, and minimalists are the people who try to make things simple. It’s an issue of how many parts you need to create a wall. We try to use very limited materials to create space. We cannot and do not want to waste material. Sometimes a building looks very low in materials, but it is important to understand the logic, or what is the importance behind the design. Kazuyo Sejima: I don't think we’re moving back [to ornamentation] but there is also some possibility that the meaning of decoration is maybe different. For example, I went to the bathroom [at 66 Portland Place], and it was very impressive, because where the floor meets the wall, there is a curve. So the modern architecture is like this wall; it is continuous. So that means it is easy to maintain, but also to keep this beauty. We can say ‘ornamental’, but this is also very functional. What lessons did you learn on the Serpentine? And about working in the UK in general? Nishizawa: What happened in Hyde Park, I’m still really impressed. This is something that we don’t have in Tokyo, in Japan. It was an example of a very mature democracy. ‘The Serpentine Pavilion would never happen in Japan’ And because it is very beautiful and happens every summer, it's kind of a space for everybody. People stay in the park, they really enjoy the park. This would never happen in Japan. How important is it for you to win an international prize at a time of growing nationalism? Nishizawa: To be appreciated by another culture means a lot. Sejima: On the other side, Japan loves Modernism that came from Europe or the UK. Nishizawa: On the idea of a monument – or to create a monument – this is something that Japanese people don’t have so much. Japanese people appreciate everything so much that they don’t have an idea to create a monument. It’s a Western idea. In Japan, everything is dynamic. Everything is growing. What advice what you give to those beginning their architecture careers? Sejima: Young people today have more possibilities. And is it more challenging today? Maybe, I think, because there are bigger possibilities but wider challenges. And what of the Osaka Expo happening right now? Sejima: The Osaka Expo shows the situation now in Japan, because we cannot use much money to build, and we have difficulty finding contractors. The expo is a new type of arrangement, trying to use natural materials. ‘When we had Covid, we had a feeling that we share the same problems’ Nishizawa: When we had Covid, we had a feeling that we share the same problems. Not only Japanese, not only Chinese, everybody shared exactly the same problem. Now we have less things that the whole world can share. Expo can be one of them, at least. So many people come to share ideas in the same place. And if we can use this opportunity to learn from each other, that’s nice.