Sumitomo Pavilion Creator’s Voice Vol.2 Yohei Shimada(Lion Architects)
Hello from the Sumitomo Pavilion.
In this interview series, “Sumitomo Pavilion Creators’ Voice,” we feature the thoughts and perspectives of the creative professionals behind our architecture, exhibits, and spatial design.
Each voice carries stories filled with passion for the Expo and the Pavilion, challenges they overcame, and non-negotiable commitments to their craft.
This time, we speak with Mr. Yohei Shimada of Lion Architects, who served as the architectural producer for the Sumitomo Pavilion.
We asked him about the warm, inviting structure built using 1,000 trees from the Sumitomo Forest.
＜Profile＞
Architect. Former Chief Architect at “MIKANi” where he was responsible for the Toyota Group Pavilion at Expo 2005 Aichi. Now involved in urban revitalization by renovating unused real estate and also operates a bakery called “Kandagawa Bakery” in Waseda, Tokyo. A true multi-hyphenate.
https://www.lion-kenchiku.co.jp/
A professional setback led me to the Sumitomo Pavilion?
About seven years ago, I experienced a major failure in my professional life. I went through a period of deep discouragement and was unsure of what I could contribute anymore. One day, I suddenly recalled the work I had done in my late 20s on the Toyota Group Pavilion at Expo 2005 Aichi—my formative years in architecture.
That experience had given me a lasting sense of confidence and purpose. So I reached out to some of the people I worked with back then.
In the summer of 2021, I met with Mr. Jun Naito, the general producer, for the first time in years. I directly asked to be involved in the Osaka-Kansai Expo. He kindly invited me to help coordinate the architecture for the Sumitomo Pavilion. I was thrilled to be involved in a Sumitomo Group Pavilion in Osaka and accepted the offer immediately.
An experimental pavilion architecture for a future society
Through this project, I learned how the Sumitomo Group had grown its business based on the development of the Besshi Copper Mine and the long-term vision that sustained that growth.
One key story was how the Group planted trees to restore the once-devastated mountains of Besshi. This sense of responsibility toward nature and the environment became central to our design challenge—how do we express that commitment through a pavilion in a celebratory event like the Expo?
Typically, Expo pavilions are dismantled after six months, so unlike permanent buildings, they only need to safely stand for that limited duration. This opens up the opportunity to experiment in ways conventional architecture doesn't allow.
The Sumitomo Pavilion is just such an experiment. We used trees from the Sumitomo Forest—including cedar planted in 1970 during the previous Osaka Expo and hinoki planted by earlier generations—to make plywood for the building’s exterior.
In normal urban architecture, it's not legally or technically feasible to use this much wood for exterior walls due to fire safety and weather resistance concerns. But this pavilion, built for a six-month festival, makes it possible. It’s a testbed for new architectural ideas.
Visitors will first encounter the exterior before entering the UNKNOWN FOREST inside. Though the shape is sharp and futuristic, the material—plywood—feels familiar and warm. That contrast creates a sense of both novelty and nostalgia.
I believe people have never seen a structure this large built entirely from plywood, and that in itself will be a memorable experience.
I’ve come to understand the significance of hosting an Expo
Before the Expo opened, the media coverage surrounding it often carried a somewhat negative tone. However, after the opening, I was relieved to see that many visitors who actually came to the venue and experienced it firsthand shared very positive feedback. As someone involved in the project, it brought me great reassurance.
To be honest, I sometimes secretly search “Sumitomo Pavilion” on social media—and I’m delighted to find that the Pavilion has been receiving excellent reviews.
It’s been 55 years since the last Expo in Osaka, and Japan has grown into a mature nation. We now live in an age where international travel is relatively easy, and people can connect with the world instantly via the internet. In such a time, the very significance of investing so much to host a World Expo in Japan is being questioned.
But seeing so many people visit the Expo and share their experiences and excitement on social media reminded me that no matter how advanced and mature our technologies become, physical spaces where people connect in real life carry ever-increasing value.
When I travel abroad, I’m constantly reminded of Japan’s unique appeal—the richness and quality of its food culture, the safety and cleanliness of its cities, the beautiful seasonal transitions. Each of these elements is something Japan can be truly proud of, and I believe it’s precisely to experience those qualities that so many people from around the world are visiting Japan now.
In this context, the Expo offers Japan’s national and local governments, as well as companies, an opportunity to showcase their cultures, initiatives, cutting-edge technologies, and ideas to the world in a real, physical space.
Personally, I’ve discovered many new things through the Expo—from innovations in Japanese agriculture and forestry to the advanced technologies developed by companies and researchers, and the rich cultural lifestyles found in regional areas. The list goes on.
I’ve come to believe that the Expo serves two major purposes:
First, it offers foreign visitors a deeper understanding of modern Japan.
Second, it creates opportunities for people to connect face-to-face in a shared physical space, even in an era overflowing with information and global connectivity through technology.
A Message to Everyone Reading
When you visit the Expo, I highly recommend entering through the East Gate. As you pass through, the Sumitomo Pavilion comes into view—its silhouette rising with the excitement of entering the celebration.
