A traditional Japanese manufacturing process is about to begin.

This is the only place in the world where it happens.

The shouts of the craftsmen echo alongside the sound of hammers beating charcoal.

It's the prologue to a story that will unfold over four days.

The team will be making tamahagane, a type of steel which combines strength and flexibility, and it's very resistant to rust.

Tamahagane , known as "miracle" steel, is almost impossible to produce even with modern technology.

This one-of-a-kind "super material" is used to make Japanese swords.

Swords made with tamahagane have garnered high praise around the world.

They're considered to be the pinnacle of the ironmaker's art.

Shoshu-style tempered line.

I've got 20,000 on this one.

At a sword show in the US, the work of Japanese swordsmiths from antique to modern finds eager buyers.

And talking to the other collectors and dealers in here, swords become an addiction.

Without tamahagane, Japanese swords would not exist.

In 2022, the production process was beset with numerous problems.

Every year in January and February, tamahagane is produced in a process called tatara ironmaking.

But due to the COVID pandemic, the process only occurred once in 2022.

And it did not go smoothly.

There are so many problems.

Since ancient times, this process has relied on the skills of craftsmen and materials from nature.

- Let’s do it.
- Yes.

Will they be able to produce the precious tamahagane?

We can only try.

The making of tamahagane is a do-or-die challenge for the 12 craftsmen.

It highlights the essence of Japanese workmanship.

Alright now.

Okuizumo in Shimane Prefecture is the only place in the world where tatara ironmaking which produces tamahagane for Japanese swords is carried out.

The four-day process begins with a Shinto ritual to pray for success.

The person in charge is Kihara Akira.

He's the chief tatara craftsman, the murage.

Kihara's been making tamahagane for 45 years.

He's the leading expert in the field.

One, two.

One, two.

Kihara is 86 years old.

He oversees the operation only during the day.

Success or failure will depend on the other 11 workers, who follow Kihara's instructions.

This will be their one chance this year to demonstrate their skills.

At first glance, the process for making tamahagane looks simple.

After burning charcoal in the clay furnace, they add iron sand and more charcoal every 30 minutes for three days and nights.

The iron sand is purified, then falls to the bottom of the furnace and hardens.

The resulting lump of iron is called kera.

The Chinese character for it combines "metal" and "mother."

Within the kera, the silvery tamagahane is formed.

But the amount won't be known until it's cracked open.

The tatara furnace has a Front and a Back.

This time, the four candidates to become the next murage are assigned to either the Front or the Back of the furnace.

They'll take turns adding the iron sand and compete to make the best tamahagane.

- Hello.
- Hi, there.

The only chance the four will have to make tamahagane and test their ability as the successor begins.

The first candidate taking the lead at the Front is Horio Kaoru.

He's considered the most likely person to succeed Kihara.

Horio was born in the area and apprenticed to Kihara when he was 24.

Kihara watches him intently.

He seems somewhat annoyed by Horio's work.

That’s spread too wide.

Make it a little narrower.

Yes.

But Horio has been doing this for 29 years.

I can’t just say, "Leave it to me."

I want to say, "Let me do it my way."

But still, he’s my master.

In fact, in 2021 when they were also forced to limit themselves to just one operation, the contents of the kera they produced were poor.

Only 180 kilograms of first-grade tamahagane was extracted, less than half of what they'd get in a normal year.

This time, Horio has convinced Kihara to change everything, from the amount of iron sand used to the clay for the furnace.

Will Horio be able to produce excellent results and demonstrate his skill to his master?

When the temperature in the furnace is right, the dim bluish flames change color.

The flame has somehow
turned bright yellow.

Yes, it’s changed.

They say the bright yellow flames are a sign of a smooth start.

When the furnace is right,
the flames will shoot up to 3 meters.

Kurotaki Tetsuya is a director at the organization in charge of the tatara ironmaking.

He's about to retire and has been scrambling behind the scenes to keep the tatara operations going during COVID 19.

He's talking to the murage candidate working the Back of the furnace.

I've been a little worried.

This side compared to the Front.

He seems to be pointing out that the flames here don't rise as high as the ones at the Front.

We'll see.

The man working the Back of the furnace is Mikami Takanori.

The quality of the tamahagane produced last year at the Back was particularly bad.

He has high hopes for this year.

To become a murage, he has to be able to tell by feel if a scoopful of iron sand weighs the requisite four kilograms.

He also has to be able to judge the state of the furnace by the flames.

If he doesn't accurately adjust how much iron sand he puts in and where, tamahagane won't be produced.

This time, somehow,
I want to pull it off.

Our job is to produce results
that will please master swordsmiths.

Mikami himself is one of the over 200 swordsmiths in Japan.

His professional swordsmith name is Mikami Sadanao.

After sweeping up all the big prizes in his 30s, Mikami is now considered "exempt from appraisal."

It's the highest rank a swordsmith can achieve.

Why can Japanese swords only be made from tamahagane?

Mikami gives us a demonstration.

First, he uses ordinary iron.

Even though it's hammered while hot, it can't be flattened.

He continues hammering, and...

- See? It broke apart.
- That’s right.

Then, he uses tamahagane.

Even if it's hammered while it's white hot, it doesn't break apart.

It begins to flatten out little by little.

Then when he folds it and continues hammering, the sides of the steel stick together and form a single mass.

The impurities embedded in the tamagahane are believed to be among the factors that produce these characteristics.

Usually, impurities are to be avoided because they cause steel to crack.

However, the impurities in tamahagane are string-like, giving the steel greater tensile strength.

The mechanism that produces this mysterious steel is still not fully understood.

This long sword Mikami made won the Commissioner for Cultural Affairs Award.

The repeated bending, folding, and flattening of the tamahagane produces the detailed patterns on the surface of Japanese swords.

Mikami made this sword from tamahagane that he forged.

We can make the materials ourselves.
That adds to the fascination.

We grow more attached to the sword.

And we can’t complain
about the tamagahane anymore.

These works of art made of steel have captivated many around the world.

In August, an exhibition and sale of Japanese swords was held in San Francisco.

The annual gathering of American sword dealers and aficionados was being held for the 32nd time.

This is a Muramasa blade from the Warring States period in the 16th century.

How much is this masterpiece worth?

It's been appraised at $85,000.

From antiques to the work of contemporary artisans, Japanese swords often sell for over 10,000 dollars each.

Japanese pieces for me outweigh the European and the other pieces.

Japanese swords are what they call, what should I say, a lethal elegance.

Japanese swords gained popularity in the US when US soldiers brought back large numbers of them after the Second World War.

But do the visitors to the show know what these beautiful objects are made from?

I think it's "tamahagane."

I think it's like a jeweled steel.

It looks like it has little pieces of jewels in it.

It's so cool that you know that term.

I think people in Japan might be surprised.

Well, I'm not sure.

The making of tamahagane is an integral part of Japanese sword culture.

Back at the foundry, it's the evening of the first day.

They're already facing difficulties.

Mikami, the murage candidate working at the Back of the furnace, is struggling to deal with a small hole used for checking inside.

It's just above the air tubes.

At the back of the hole, some impurities or slag are burning.

They're sagging down and blocking the hole.

Some of the iron sand has reacted to the clay in the furnace and turned into slag.

While the slag helps keep the furnace temperature high, it can also block the air intakes and keep air from entering.

In the worst case, the fire goes out, dooming the operation to failure.

To keep that from happening, they have to drain some of the slag through holes called yujiana.

It's been 12 hours since they started shoveling in the iron sand.

The battle is on to deal with the accumulating slag.

The slag is draining well here.

At the Front of the furnace, the slag is flowing out from the yujiana and appears to be draining nicely.

It’s so-so.

- It looks ok.
- It’s not bad.

On the other hand, at the Back...

The slag isn't coming out.

Good morning.

And it's time to change shifts.

I wanted to bring it
to a beautiful end but...

Now, it really begins.

Sato Hideyuki studied metal refining technology and thermodynamics as a researcher in graduate school at Osaka University.

He's the theorist in the group.

- Let’s do it.
- Yes.

First, he examines the holes, and finds that they're pretty clogged up.

The mouth of the air tube just below is likely blocked with slag.

They quickly probe the yujiana to try to drain it.

It's blocked with hardened slag.

The one on the left is especially bad.

Logic is Sato's strong suit.

He analyzes the furnace situation and comes up with a plan.

Sprinkle it on.

He decides to put the charcoal in before the iron sand.

Half a basket.

He calculates that by raising the temperature of the furnace, they can prevent the slag from hardening and maybe even melt some of the hardened slag.

First, he works on the yujiana on the right.

As he'd hoped, the slag has gotten a little softer.

Here, along the right edge.

Push it inside.

Diagonally, to the left from the edge.

It’s starting to melt.

The slag's coming out.

Next is the yujiana on the left.

Aiming at the gap between the kera lump and the wall, Sato uses all his strength to shove the pole in.

There.

Right here, at this spot.

Once more.

Here we go.

They are finally able to remove a large piece.

They've somehow succeeded in draining the slag.

It’s draining well.
That’s solved.

But what impact will this delay in draining the slag have on the tamahagane?

They won't know that until the operation is over and they crack open the kera.

Sato normally works at a steel plant in the city of Yasugi in Shimane Prefecture.

The 120-year-old plant has been engaged in tatara ironmaking for many decades.

Eight of the 12 tatara craftsmen here, including the murage, Kihara, work there.

Today again, safety first.

Sato designs the facilities of the Yasugi plant and supervises maintenance.

He joined the company after graduating from an industrial high school.

His company urged him to unravel the mysteries of tatara ironmaking and sent him to graduate school as a researcher.

But...

Normally, after working for about 10 years,
you can somehow understand the work.

The industry standards and so on.

But not for tatara ironmaking.

Things don’t go well.
Then next time, we still don’t get it.

I keep going because
I still can’t figure it out.

The company has supported tatara ironmaking with technology and personnel.

But now, it has been decided that the company will be sold to an investment fund.

What will happen to the last surviving tatara ironworks?

Until about 130 years ago, Okuizumo in Shimane was one of Japan's major industrial areas.

Tatara ironmaking flourished because iron sand could be mined from many of the terraced rice fields.

If you put a magnet in the Hii-kawa River, which runs through Okuizumo, you can easily pick up iron sand.

This mountainous area is rich in high-quality iron sand.

When human development tore away the sides of the mountains, soil and water flowed down, forming shallow terraced ponds.

That's where the iron sand accumulated.

With so much raw material available, tatara ironworks sprang up throughout the area.

Until Western-style ironmaking was introduced at the end of 19th century, over 80 percent of the iron produced in Japan came from this region.

Tatara ironmaking all but disappeared after the end of World War II, but was revived in 1977.

Kihara and other ironworkers were apprenticed to two men who'd been involved in ironmaking during the war.

Swordsmiths around Japan were demanding tamahagane.

But the revival of tatara ironmaking got a big boost from the Ise Shrine.

Once every 20 years, a new shrine is built near the existing one.

A sword is dedicated at the completion ceremony, and nothing but tamahagane will do.

What is this?

It’s the Sugari No Ontachi sword,
a sacred treasure of the Kotai Shrine.

It’s well-known as a treasured object
of the ancient grand shrine.

The Sugari No Ontachi sword.

The pattern on the straight blade resembles a beautiful wood grain.

The handle shows two tail feathers of a crested ibis.

Even among the other sacred treasures dedicated at the construction ceremony, its graceful elegance stands out.

The blade was made in 1953 for the first ceremony after the war.

They were able to make the blade by cobbling together pieces of tamahagane that still remained.

Since there was a shortage
of the base material, Ise Shrine was very interested in the revival
of tatara ironmaking in 1977.

It assisted in various ways and
was able to contribute to its revival.

The meticulously crafted base metal
and the fresh blade pattern couldn’t have been achieved without
the ancient Japanese iron and steel.

That is why we place such importance
on tamahagane.

In addition to swords, tatara-produced iron is also made into tea kettles used in the Japanese tea ceremony.

And to make highly durable nails, clamps, and other implements said to last for over 1,000 years.

These are essential for the restoration of cultural properties such as temples and Buddhist statues.

This craftsmanship supports Japan's culture even more than its economy.

Tatara ironmaking is a pillar of Japanese culture.

A day has passed since the ironmaking operation began.

The bright yellow flames have risen higher, and are bursting out from the yujiana holes.

The kera iron lump should be growing bigger but the furnace is still unstable.

If they take their eyes off of it for five minutes, things could suddenly change.

They can't let down their guard for even a moment.

Hi, Mr. Horio.

- It’s been over 30 hours.
- I’ve lost all track of time.

You look skinnier.

Really? That’s a plus.

He'll keep adding the iron sand until eight in the evening without sleep.

Things going well?

We’re on course.

Above that.

Traditionally, the murage master must direct the operation for three days and nights without rest.

There, straight up.

This time Horio is taking on the challenge of managing the iron sand work for two days.

Let’s do it.

However, fatigue seems to have dulled his senses.

He's started using the scale to measure the iron sand.

If he loses his feel for the weight of the shovel, he might misjudge the quantity of sand and where to put it.

That could result in problems with the furnace.

Just before eight pm, Miura Yasuhiro takes over for Horio at the Front.

And he notices something.

Having a tough time.

How do you know?

The charcoal level is not falling.

It’s not going down.

That means the combustion inside the furnace is inadequate and the iron sand might not melt properly.

Will it go down?

But how long it takes...

This has happened while the murage, Kihara, is absent.

They're changing shifts without being able to solve the problem.

Let’s do it.

How is it so far?

I can’t say things are great.

For lots of reasons.

What are they?

For example, the base materials.

You’re using new iron sand.
That’s not going well?

Maybe. We also changed
the furnace a bit.

That’s also a possibility.

- It’s still just the second day.
- Yes.

We’ll recover.

Miura has taken over for Horio.

He's using trial and error to find a way to burn more charcoal.

Why isn’t it going down?

The charcoal still hasn't burned down.

We can only try.

Alright.

But he's got another trick up his sleeve.

The charcoal isn’t burning down well.

Only this side.

He instructs Ando Yusuke, who's in charge of the charcoal, to take the unusual step of inserting large logs that burn easily.

But then...

- Hold off.
- Yes, OK.

He withdraws his order.

The combustion has improved and the charcoal is beginning to burn.

It seems that Ando has used his own judgment to adjust the size of the charcoal pieces and their placement in the furnace.

This piece is big.

These are broken up.

We first put the small pieces in the places
where the charcoal is burning down well.

Bigger pieces go where
we want it to go down.

It might look kind of random,
but there’s thought behind it.

I’m really grateful for
a charcoal guy like him.

Even without saying anything,
he grasps what I’m thinking.

I’m truly thankful.

Tatara ironmaking requires everyone to work together.

That's very clear when it comes to preparing the furnace bed.

Synchronizing their strength and voices, they take three days to complete it.

Naturally, everyone is involved in building the furnace.

As we focused on the four aspiring murage, Miura had something to tell us.

If the murage isn’t there,
we can’t operate the tatara furnace.

But the murage’s efforts alone
won’t make it happen.

It’s all the result of everyone
coming together and working hard.

Late in the evening of the second day, the back-and-forth battle with the furnace continues.

If things go well, on the third day the kera lump of iron should form and grow right up to the level where the furnace walls collapse.

Mr. Kihara, what’s the situation now?

Not quite there yet.

They’ve been having some problems.
They’ve fixed them for the time being.

The flames should come out with
more force from all the yujiana holes.

There are so many issues.

The flames coming out of the yujiana are weak.

It's possible that the air inside the furnace isn't flowing properly.

They act like murage, but they
haven’t mastered it.

In order to produce the highest-quality tamahagane, Kihara has devoted himself to his craft.

He probably feels frustrated with his apprentices.

Looks like you’re not getting good kera.

Horio has been away from the furnace, so he doesn't know what's going on.

That's why a murage should always be present for all three days and nights.

In the meantime, Miura has stayed up all night with the furnace.

Hi, Mr. Miura.

Mr. Kihara said that things
aren’t going very well.

Really?
I don’t think that’s the case.

The team's tenacity through the night has brought the furnace under control.

Miura thinks it's a temporary problem.

Later, Kurotaki notices a change in the flames.

Look closely at that area.

The flames shooting out over the edge of the furnace are a sign that the situation has improved.

All right.

Miura has finished his stint as murage just as the furnace has been stabilized.

The mud on his clothes and burns on his skin testify to his struggle.

Meanwhile, how is the swordsmith Mikami, at the Back of the furnace, faring?

He's started using the scale.

Mikami is 66.

On day three, he has taken a rest, but the work has to be taxing.

His strength sapped by the flames, his body must be screaming for relief.

Mr. Mikami, are those burns
on your face?

My skin is delicate.

Shows how hard I’ve been
working, doesn’t it?

Tanaka Fuminori, who's in charge of loading the charcoal at the Front, decides to forgo his break and rushes in to help at the Back.

Here I go.

It seems the kera has gotten bigger and blocked the yujiana.

If you hit it too hard,
you’ll break the furnace wall.

It has to last one more night.

They don't have any digital instruments to assess the situation inside the furnace, or power tools to help them work more efficiently.

Using only primitive tools, they rely on their physical strength to probe inside the furnace.

The 12 tatara craftsmen carry out the entire production process by hand.

There are no short cuts.

But that seems to make them enjoy the whole operation even more.

Wait. Hit it only once more
diagonally above.

Without assistance from technology, they use their bodies as sensors to pick up small details and make discoveries.

This way of working calls to mind the essence of Japanese craftsmanship, with its reputation for excellence and dedication.

Alright now.

It's early in the morning on the fourth and final day.

They've finished shoveling in the iron sand for three days and nights, and are now ready to retrieve the kera.

Has it formed successfully at the invisible bottom of the furnace?

At 6 am, we’ll finally start
breaking apart the furnace.

It’s dangerous so be extra careful
not to get burned.

The process begins.

For them, every time is different.

The tatara furnaces they build may be destroyed.

But through that process, the knowhow will remain, to be passed down to the next generation.

One, two, heave.

Once more.

It’s coming.

Next.

Ready?

The heat from the huge amount of burning charcoal is released in a flash, in a blast reaching hundreds of degrees.

Beneath that inferno of charcoal, the kera has appeared.

The shape is good.

It’s eroded well lengthwise,
forming the kera.

It’s almost flat.

The kera weighs about three tons.

After it cools, they'll break it apart to remove the tamahagane.

How much of it will be the glittering silver kind that they want?

Will the results be as disastrous as last year's?

Kihara has produced tamahagane over 160 times.

Consequently, his standards are very high.

It’s not good enough.

It won’t be very good.

How is it compared to last year?

Looks like it’ll be about the same.

Good morning.

The moment has arrived: time to crack open the kera.

Everyone looks tense.

Have they heard murage Kihara's prediction?

If the result is poor for the second straight year, the impact on Japanese sword making will be huge.

First, they will split open the section that Horio and the Front team were in charge of.

How is it?

It’s good steel.

Looks like first-class A grade.

Look at this.
The coloring is perfect.

It’s from the Front.
Not the Back.

The sense of relief is palpable.

It’s what we planned.

Just as planned.

This steel is better than last year’s.
It’s just what we were aiming for.

- You were a bit discouraged for a while.
- Yes, I was.

The second day was tough.
I was worried.

But seeing this, I’m relieved.

What about the Back, the section the theorist Sato and the swordsmith Mikami were responsible for?

It's a lot better than last year.

But there's a black layer sandwiched between the silver sections.

This is where the problem happened
during the operation.

It went well and then went bad.

I didn’t expect a good result.

It’s regrettable. I wanted to
make a perfect kera.

I have to work harder.

Kihara had low expectations.

What does he make of this year's results?

How is it?

It’s fine, good.

The quality of the steel itself
is very good.

Everything is here.

But the question is
how much of it is first class?

That’s the one criterion for appraisal.
I think they’ll get a pretty good yield.

This year's operation allowed Kihara to see how much his apprentices have grown.

Mikami went back to making swords.

Using the tamahagane that he himself produced, he's reproducing a famous type of sword made 800 years ago.

How can I obtain a stable supply
and continue my work?

This is the only place in the world
that has a tatara furnace.

I hope to support it
as long as I’m physically able to.

And then there is the murage, Kihara Akira.

Along with Miura and Horio, he's working at an event where people can experience using a mini-tatara.

It’s hot.

They want to expose young people, raised in the digital era, to the adventure and fascination of craftsmanship.

Hot?
A little more.

Try as much as possible to use
your bare hands.

Don’t wear gloves.

My hands are weak.
Can I wear gloves?

It’s important to feel
with your bare hands.

This time, the 12 tatara craftsmen produced about 400 kilograms of first-grade tamahagane.

That's double last year's yield.

Now, Japanese swordsmiths will transform this miracle steel into works of art that will again amaze the world.