How an iconic Japanese gate has stood in the sea for more than 150 years
Picture this.
You’re standing on the island of Miyajima, just outside Hiroshima. In front of you, a huge vermilion torii gate appears to be floating on the sea.
At high tide, the water surrounds it.
At low tide, you can walk across the exposed sand and stand right beside its enormous wooden pillars.
It looks almost impossible.
And then you learn something even more surprising:
The famous 60-ton gate isn’t anchored deep into the seabed.
It essentially stands on its own weight.
Wait… what?
A 60-ton structure that simply… stands there
The O-torii of Itsukushima Shrine is one of the most recognizable images of Japan.
The current gate was built in 1875 and is considered the ninth O-torii since the Heian period. It stands about 16.6 meters (54 feet) high, stretches more than 24 meters (79 feet) across, and weighs approximately 60 tons. It is also designated as a National Important Cultural Property of Japan.
But unlike what you might expect from a massive structure standing in tidal waters, its main pillars aren’t driven deep into the seabed.
Instead, the gate rests on a specially prepared foundation.
And that is where the clever part begins.
The Japanese answer to soft ground: “thousands of piles”
The seabed around Miyajima isn’t exactly the kind of solid foundation you’d choose for a giant wooden gate.
So ancient builders developed a technique known as senbon-gui, which literally means “thousand piles.”
Pine logs were driven into the soft ground beneath the gate to stabilize the area. The ground was then capped with stone, creating a much firmer base for the enormous structure.
The O-torii essentially sits on this foundation rather than being rigidly fixed deep into the seabed.
Think about that for a moment.
The builders weren’t trying to make the gate immovable.
They were creating a stable place for it to stand.
That distinction is important.
So why doesn’t it fall over?
Here’s where the design gets even more interesting.
The O-torii has four supporting pillars, with two massive natural camphor trees forming the main pillars. Camphor wood was a particularly practical choice because of its durability and natural resistance to insects and decay.
But the builders also had another trick.
Inside the large box-shaped beams near the top of the gate are stones used as counterweights.
According to the Miyajima Tourist Association, the stones weigh approximately 4 tons in total. They help lower the center of gravity and give the structure additional stability.
So instead of creating an enormous foundation and locking the gate into the ground, the design uses:
weight + balance + geometry + a little flexibility.
That’s a remarkably simple idea.
And perhaps even more remarkably, it has worked for generations.
Built to live with the sea—not fight it
This is the part of the story that I find especially fascinating.
When we think about modern engineering, we often imagine strength as something rigid:
Make it stronger.
Anchor it deeper.
Bolt everything down.
Don’t let it move.
But the O-torii represents a very different approach.
The structure is heavy enough to remain stable, but it isn’t designed to completely resist every movement caused by waves, wind and the environment.
In a way, it works with its surroundings.
Imagine standing in strong wind with your knees locked.
You might feel very stable—until the force becomes too much.
Now imagine slightly bending your knees.
You can move with the force.
You may sway, but you’re much less likely to fall.
That simple idea of allowing a structure to respond to its environment is one of the things that makes traditional Japanese architecture so fascinating.
And then there is the wood
The two enormous main pillars are made from natural camphor trees (kusunoki).
Not ordinary lumber.
The pillars were made from whole tree trunks, selected for their size and durability. The four smaller supporting pillars are made from cedar.
Of course, even excellent wood isn’t invincible.
The most vulnerable part of the structure is also the part closest to the water.
The bases of the pillars are repeatedly exposed to seawater, moisture and marine organisms. Over the years, those conditions take their toll.
This is why the O-torii has never simply been “built once and forgotten.”
It has been repaired and maintained again and again.
And that brings us to another important Japanese idea:
preservation doesn’t necessarily mean leaving something untouched.
150 years old—but not frozen in time
The O-torii underwent a major restoration beginning in 2019, with the work completed in 2023.
During the restoration, the structure was carefully examined and damaged areas were repaired. Components were individually inspected, wooden sections were restored, and deteriorated materials and hardware were addressed.
This is where something particularly interesting happens.
Traditional craftsmanship and modern technology don’t have to be enemies.
A historic wooden structure can be protected using modern materials and engineering techniques—while still respecting the original design and craftsmanship.
In other words:
Preserving tradition doesn’t mean refusing to use new technology.
It means knowing what should be preserved—and what can be improved.
The lesson behind the famous red gate
Millions of people photograph the O-torii because it is beautiful.
But once you understand how it stands, you start looking at it differently.
You stop seeing only a beautiful red gate in the ocean.
You start seeing a lesson in problem-solving.
The builders had a difficult environment:
- Soft ground
- Powerful tides
- Salt water
- Wind
- Storms
- Earthquakes
- A massive wooden structure
And instead of trying to completely control nature, they designed around it.
They used the weight of the structure.
They used the properties of the wood.
They used counterweights.
They strengthened the ground.
And they allowed the structure a certain amount of movement.
That combination of simplicity, observation and craftsmanship is what makes the O-torii so remarkable.
A different way of thinking about “Made in Japan”
When we talk about Japanese craftsmanship, it’s easy to focus on the finished product.
A beautiful knife.
A carefully made piece of pottery.
A traditional wooden object.
A beautifully designed package.
But the deeper story is often what interests me most.
Why was it designed this way?
What problem was the maker trying to solve?
What did they understand about the materials they were working with?
And what did they learn from nature?
The O-torii is a spectacular example.
It isn’t impressive simply because it is 60 tons.
It is impressive because someone figured out that 60 tons could stand in the sea without being buried deep into the seabed—and that the solution didn’t have to be complicated.
Sometimes, good engineering isn’t about adding more.
Sometimes, it’s about understanding what you already have.
And perhaps that is one of the most interesting things about Japanese craftsmanship:
The smartest solution isn’t always the strongest one.
Sometimes, it’s the one that knows how to stand—and when to move.
A closer look at Japan
At AK JAPAN, we’re interested in the stories behind Japan’s products, places and craftsmanship.
Because “Made in Japan” is more than a label.
Behind it are generations of knowledge about materials, nature, balance, patience and making things well.
The next time you see that famous red torii floating off the coast of Miyajima, you might see more than a beautiful photograph.
You might see 60 tons of Japanese ingenuity, standing quietly in the sea.