Japan Pavilion at Osaka Expo 2025
Japan Pavilion at Osaka Expo 2025

The Japan Pavilion is the flagship pavilion by the host country (Japanese Government Pavilion). Therefore, it’s automatically one of the most popular pavilions at Osaka Expo 2025.

However, the pavilion is not oriented for entertainment, amusement, or a cultural showcase (no cherry blossoms, no geisha, no Mt. Fuji, etc.). It’s more educational, scientific, and thought-provoking about how we can reduce and recycle organic waste.

This blog post explains the Japan Pavilion’s basic ideas and science behind the exhibits. You will then appreciate and enjoy the pavilion much better.

  • Japan Pavilion is actually a recycling plant processing and converting the expo site’s organic waste (food scraps, paper waste, etc.) into water and electricity.
  • The pavilion’s main theme is Junkan (循環), which refers to an endless cycle of things being created, used, and eventually broken down only to be transformed into something new. An infinite loop where things start and end at the same point while taking different forms. What goes around, comes around.
  • That’s why the shape of the pavilion building is circular.
  • Pavilion exhibits are heavy on bioscience centering on beneficial microorganisms.
  • The pavilion was designed to be dismantled easily to reuse or recycle the building materials (cross-laminated timber or CLT) and furniture.
  • Pavilion highlights include 32 green Hello Kitty designed like algae and Martian meteorite rocks found in Antarctica.

You can stand in line without reservations during 9:30 am to 10:30 am and after 7:00 pm.
Location: East Gate area outside the Grand Ring.
Pavilion hours: 9:30 am–9:00 pm
Official website: https://2025-japan-pavilion.go.jp/en/information/
Audio guide: https://audioguide.2025-japan-pavilion.go.jp/en/entrance/

Inside the Japan Pavilion

Japan Pavilion floor plan.
Japan Pavilion layout.
  • The pavilion is a low-rise, circular structure made of wood and glass with a hole in the middle for an artificial pond. The design symbolizes the junkan cycle. The building was also designed to be easily dismantled after the expo to recycle or reuse the building materials.
  • Three main areas called Plant, Farm, and Factory. (Photos below.)
  • Exhibits explain how the pavilion functions as a recycling plant processing the expo’s organic waste.
  • Crowd pleasers include 32 green Hello Kitty shaped like different algae and Martian rocks (including touchable ones) from a meteorite discovered in Antarctica.
  • The pavilion tour takes about 40 minutes. For the most part, you can go at your own pace to look at the exhibits.
  • Japan Pavilion’s small Official Shop is inside and outside the pavilion. Both sell the same merchandise.
  • The pavilion is fully equipped with restrooms, nursing rooms, baby changing stations, and wheelchair accessible facilities.
  • For rubber stamp collectors, there’s a rubber stamp outside the pavilion for anyone to use, and another different stamp for pavilion visitors only.

Plant AreaConverting organic waste into water…

The pavilion tour route may start from any of the three areas since each has its own entrance, but when I went, we started from the Plant Area.

This is where the expo site’s organic waste is processed into water, heat, and electricity. Things at the end of their useful life (waste) are transformed anew into something useful thanks to microorganisms.
Audio guide: https://audioguide.2025-japan-pavilion.go.jp/en/entrance/

Intro to the Plant Area.
Intro to the Plant Area. Microscopic life, it speaks…
Hourglass at the Plant Area entrance.
Hourglass at the Plant Area entrance.

The entrance to each of the pavilion’s three areas has a large hourglass. It represents an endless ending (upper half) and endless beginning (lower half) in an endless cycle.

Conveyor belt of organic waste
Conveyor belt of organic waste feeding into the pavilion’s waste-processing plant. There’s a banana peel…

A large conveyor belt brings food scraps, disposable cutlery, and paper waste into the pavilion’s recycling factory. All the expo site’s organic waste is brought here. Microorganisms are used to decompose and transform the organic waste into water, heat, electricity, carbon dioxide, and nitrogen.

Lighting thanks to fermentation...
Garden of Light – “Lit by fermentation?”

This room of flashing polka dots supposed to represent the rebirth of the processed organic waste. There are 37 large tanks below fermenting organic waste with microorganisms. The waste is broken down into proteins and carbohydrates which become amino acids and sugars.

Methane-producing bacteria then produces biogas used to generate electricity. This process reduces the amount of organic/food waste that needs to be incinerated, thereby lowering CO₂ emissions.

Exhibits showing how organic waste can be transformed into water, heat, and electricity.
Exhibition room where the pavilion is “eating.” It’s about koji mold for food, and decomposing biodegradable things..
Bowl made of biodegradable plastic being broken down by microorganisms.
Bowl made of biodegradable plastic being broken down by microorganisms.
Koji mold used to make Japanese food and drink
Different koji mold for making Japanese food and drink such as miso and sake (Nihonshu).

This exhibit shows genetic renditions of koji mold used to make sake, soy sauce, and miso.

This room has five biodegradable bowls in separate tanks shown in different stages of decomposition. The CO₂ produced by the pavilion can be used to make different materials like biodegradable plastic.

On the far end of the room, we can see plant equipment below…

Japan Pavilion's central courtyard is round pond.
Japan Pavilion’s central courtyard has a round pond of purified water and walking path.

After the Plant Area, we step outside to the open-air center of the pavilion to see a round pond with crystal-clear water. The clean water was produced from organic waste thanks to microorganisms.

Inner courtyard pond
Round pond with crystal-clear water.

Farm AreaFrom water to materials…

After seeing the pond, there was a short wait to reenter the pavilion to see the Farm Area. The first exhibit was Martian rocks. First there were small Martian rocks which we could touch, then a large one (rugby ball size) behind a glass case.

Japan's Martian rock
Japan’s Martian rock displayed for the first time to international visitors. One of the largest known Martian meteorites in the world. Belongs to the National Institute of Polar Research.

This Martian meteorite rock was discovered on November 29, 2000 by a member of the 41st Japanese Antarctic Research Expedition on the Yamato Glacier in the mountains of Antarctica. Named Yamato 000593, this rugby ball-size rock was brought back to Japan for further analysis.

Through microscopic examinations of thin slices of the rock, the unique mineral patterns confirmed that Yamato 000593 was a Nakhlite—a rare type of meteorite originating from Mars. Gas trapped within the rock matched data from Mars exploration missions, providing definitive proof of its Martian origin.

Roughly 10 million years ago, a massive asteroid crashed into Mars that sent rocky debris into space. The rock fragments drifted around the sun for 10 million years while heading toward Earth. Then tens of thousands of years ago, this particular rock entered Earth’s atmosphere and survived the fiery descent and miraculously landed on Antarctica instead of the ocean where it would never be found.

Antarctica’s freezing environment preserved the rock for tens of thousands of years until it was discovered in the snow as an unusual, black rock with shiny, greenish mineral inside.

Antarctica, with its white ice fields and glaciers, is the world’s richest source of meteorites. Japanese scientists based at Showa Station in Antarctica have long conducted systematic searches there, and their efforts paid off with the discovery of Yamato 000593.

Among more than 17,000 meteorites cataloged by Japan’s National Institute of Polar Research, only 15 are confirmed to be from Mars, and Yamato 000593 is just the fourth known Nakhlite. It stands out not only for its rarity but also for its size—measuring 29 cm wide and weighing about 13 kg, the second largest Martian meteorite ever found on Earth. Despite its delicate structure, it has remained intact thanks to Antarctica’s frozen environment.

Yamato 000593 is especially valuable because it offers clues about Mars’ watery past beneath the planet’s surface. The rock contain minerals which could not have formed without water, further solid evidence of water existing on Mars. Water on Mars inspires hopes for future human exploration and habitation on Mars. I don’t have any desire to live on Mars though.

Farm Area concept
Farm Area concepts.

The Farm Area shows how the water, heat, electricity, carbon dioxide, and nutrients such as nitrogen extracted from organic waste can be combined with other things to produce different things like fuel, food, medicine, and even fabrics.

The CO₂ (carbon dioxide) extracted by processing organic waste can be a raw material to make different things like biodegradable plastic to make bowls. The CO₂ is stored in these gas cylinders.

The power and potential of algae…

Algae factory for Botryococcus
Bathtub-size tanks cultivating a green algae species called Botryococcus which produces lots of oil. It’s seen as a biofuel which may replace petroleum.

The pavilion throws new light on algae which most of us might regard as a nuisance in goldfish aquariums at home. The fact is, there are over 300,000 kinds of algae, from microscopic size to meters long (edible seaweed like wakame and konbu). They grow in both freshwater and the ocean.

Algae has been around for a whopping 3.5 billion years, long before humans first walked the Earth 2 million years ago. If it weren’t for algae, there wouldn’t be enough oxygen for humans to live on Earth. They originated from the ocean and through photosynthesis for many years, increased the amount of oxygen in the atmosphere enough for humans to survive.

It converts carbon dioxide and water into oxygen and sugar through photosynthesis. Certain species of oil-producing algae can also become an alternative fuel for petroleum. Research and development is being conducted to see how algae can better benefit us and the Earth.

The pavilion presents the potential of algae technologies by Japanese companies to benefit the environment and be profitable as well.

Algae only needs light and water to grow. Cultivating algae through photosynthesis is eco-friendly. It requires little water since the water can be recirculated. Algae also doesn’t require soil, so it can be grown in diverse environments even in a dry desert.

Although the technology is there to harness the benefits of algae, the scale is not there yet. Large-scale algae cultivation is required to make it financially feasible. Algae plants requires huge financial investments.

Hello Kitty algae.
Hello Kitty algae.

One highlight of the Japan Pavilion is Hello Kitty in the shape of 32 different algae. This room has two walls mounted with 32 green Hello Kitty shaped like algae.

Each one is identified and described on an explanatory board. Hello Kitty is from Sanrio Company, Ltd., a co-sponsor of this exhibit.

Left photo: Botryococcus algae (oil producing) as Hello Kitty.
Right photo: Kombu seaweed as Hello Kitty.

Each algae is different, all are wonderful...
Each algae is different, all are wonderful…
advantages of algae.
Room explaining the major properties of algae.

After Hello Kitty, this room has round exhibits explaining the incredible things algae can do.

Algae can absorb 14 times as much CO2 as a cedar tree.
Algae can absorb 14 times as much CO2 as a cedar tree.

Algae can be used to efficiently produce protein and oil, absorb carbon dioxide, and consume water. It has great potential to create sustainable materials and alternate fuels to replace conventional petroleum.

Algae curtain" which is a photobioreactor
“Algae curtain” which is a photobioreactor using light to nurture algae.

The next room has impressive “algae curtains,” a web or netting of many small tubes with algae flowing through and continuously photosynthesizing oxygen along the way.

It’s a photobioreactor cultivating blue-green algae called spirulina with artificial light and very little water. Being full of vitamins, minerals, and protein, this algae is already used as a food source. The algae curtains are relaxing, akin to forest bathing. The wall mirrors make it look larger than it really is.

Vials of biodegradable plastic granules.
Vials of biodegradable plastic granules.

Then you see this wall of vials containing what I first thought were grains of rice. They are actually biodegradable plastic granules. They can be used to make plastic things like bowls and file folders.

Now you're part of the cycle too...

Factory AreaFrom raw materials to things…

Factory Area has two main rooms. The first room is a small factory making biodegradable stools. Furniture in the pavilion are biodegradable.

Robotic factory making stools.
Robotic factory making stools.

The factory below has robotic arms and a 3D printer creating stools made of bioplastic resin mixed with algae. The stools are biodegradable. The stool printed in different stages is also shown. You can see a finished stools up close in the next room.

3D printer making a stool made of bioplastic resin mixed with algae.
3D printer making a stool made of bioplastic resin mixed with algae.

The Japan Pavilion recommends making toys and playground equipment with biodegradable plastic instead of petroleum-based plastic. It’s to reduce the harmful impact on the environment during production and disposal. I would definitely buy things made of biodegradable plastic if they were more widely available.

These stools use no fasteners or adhesives. After the expo ends, the stools can be crushed into powder and reused.

The next room is a gallery of “soft things” designed for easy deconstruction. It makes it easier to repair which makes it last longer. Also easier to recycle.

Sample products include wooden bath buckets, balls, furoshiki wrapping cloth, and transformer robotic toys. They don’t use any fasteners or adhesives. Parts are easily replaceable.

It’s actually a traditional Japanese approach or technique for making things.

Japanese dressmaking.
Japanese dressmaking with replaceable fabric parts.
Tokyo Skytree
Tokyo Skytree

Tokyo Skytree is another famous example of Japan’s “soft” construction. During an earthquake, the tower has a flexible pillar in the middle which sways in the opposite direction of the tower’s shaking to counteract the tower’s shaking. It thereby reduces the tower’s swaying. Since the pillar is not connected to the tower structure, it can sway independently from the tower itself. This central pillar can also be found in pagodas in Japan.

Doraemon manga
Doraemon manga explaining Ise Jingu Shrine’s deconstruction and reconstruction of its main shrine every 20 years.

Another famous example of the construction and deconstruction cycle is Ise Jingu Shrine in Mie Prefecture. A Doraemon manga is used to explain the famous event held every 20 years when the main shrine building is dismantled and a new one built on an adjacent plot with much fanfare spanning several years. The old shrine’s parts are reused by other Shinto shrines. The next reconstruction (already in progress) will be completed in 2033.

"soft" objects made for recycling
Other “soft” objects made for recycling such as uniforms, packaging, and the pavilion itself.

Even the Japan Pavilion itself was designed as “soft” to make it easy to dismantle and recycle the materials after the expo ends. The building, furniture (benches, stools, and signboards), and even the pavilion attendants’ uniform were designed to be recycled into something else.

The building’s walls were made with cross-laminated timber (CLT) for easy dismantling and recycling.

Attendant uniforms (black) were made with 100% recyclable polyester fabric. (I guess that means they cannot keep their uniforms as a keepsake.)

rotating disk covered with diatomaceous earth
Rotating disk covered with diatomaceous earth.

The pavilion’s final exhibit is this large, rotating disk covered with powdery diatomaceous earth. A line of water drops shoots down to the disk to create water spots in different patterns. The water droplets quickly dry up and disappear.

Diatomaceous earth is fossilized algae that can absorb and disperse moisture. It has a wide range of uses including filtering material, mild abrasive in toothpaste, cat litter, and soil for bonsai plants.

This means you will someday transform into something else and return in the cycle of life.

The pavilion’s last room has a showcase of sample products made with algae, such as skin care products and even a dress. There’s also a small gift shop. Another small gift shop is outside the pavilion.

The exit path is similar to the entry path.

Japan Pavilion at night
Japan Pavilion at night.

And that was the Japan Pavilion. This blog post should help you better understand and appreciate the pavilion.

Japan Pavilion

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