Athletes fight against gravity, pushing themselves to the limit as they race up endless flights of stairs.

This is Stairclimbing.

Japan is a leader in the sport, and is home to many of the world's top competitors.

We take a closer look at two Japanese athletes vying to win the Stairclimbing World Championships.

We have featured the sport of Stairclimbing before, back when it was known as Vertical Running.

The rules of Stairclimbing are simple; competitors race up a flight of stairs, and the first to the top wins.

The World Championships have been held in Japan for the first time.

We're going to take a look at the results,

as well as the unique techniques and strategies used by elite Stairclimbers that take them to the top in the fastest time possible.

Stairclimbing has a long history.

The first ever race was held at the Eiffel Tower in Paris back in 1905.

Today, Stairclimbing races are held in cities around the world, and the sport is growing in popularity.

Athletes must keep on aiming for the top.

They are timed individually and the fastest wins.

The climb is extremely grueling.

Some races are made up of more than 1,000 steps, leaving some athletes completely drained of all energy.

For shorter races of around 400 or 500 steps, Stairclimbers must sprint up the stairs as fast as they can.

It's all about speed and lower body strength.

To win, competitors must push themselves both physically and mentally.

This is Watanabe Ryoji.

In 2022, he came second in the Stairclimbing World Championships and he's won several other international competitions.

Watanabe is known for his signature technique of using the handrails to speed through each landing.

Just before he reaches a landing, he grabs the handrail of the next set of stairs, and spins himself around.

This ensures he doesn't lose any speed.

If you don't seize hold of the handrail while you climb, you'll need to take one or two extra steps.

Here, let me show you.

1,2,3,4,5; it takes five steps to do what you can do in three if you use the rail.

You'll also find that you use more energy if you don't use the rails to move through the landings.

This technique reduces time and conserves energy.

So, it's a very important part of the climb.

Watanabe trains hard to make the most out of this technique.

He incorporates this particular exercise into his training.

Supporting his body weight on both hands, he kicks his legs into the air.

He says that doing eight sets for 20 seconds at a time

not only improves the strength of his abdominal muscles and lower body, it also helps him stabilize his core.

Stairclimbing champions are those who train vigorously every day

and develop fine-tuned techniques designed to climb just that little bit faster.

One elite female athlete from Japan has an outstanding record on the global stage.

But what makes this Stairclimber so formidable?

This is Tateishi Yuko.

At the 2022 World Championships, she finished in second place.

This year, she's a leading contender for victory.

Tateishi began her career as a middle-distance track and field runner.

She then tried her hand at other sports including trail running.

After taking an interest in Stairclimbing, she met Watanabe Ryoji for the first time.

He encouraged me to have a go at Stairclimbing because he thought I'd enjoy it as much as he does.

Around that time, there was a race open to the general public being held at Abeno Harukas.

The winner's prize was a ticket to a major international competition.

So, I entered, and I actually won that event, which led me to take up the sport in earnest.

"That's impressive!"

Tateishi is mother to a two-year-old boy.

So, it must be difficult for you to balance your athletic career and motherhood.

I have a young son, but as this sport's about pushing yourself to the limit in a short period of time,

my training's short, too.

I aim to finish my training before my son goes to nursery,

so I wake up around 4 o'clock in the morning, and make breakfast for him.

My parents keep an eye on him for me while I'm training.

Then once I've finished training, I'm back home before six when my son wakes up.

I go back out at eight and work until four, then I pick my son up from the nursery.

I come home, make dinner, and then go to sleep at the same time as him.

That's my daily cycle.

Ryoji also has a son, so he knows how hard it can be, which is why he encourages me.

18 months ago, Tateishi took part in a short race up 415 steps.

In Stairclimbing, short races are usually won by only one or two seconds.

Letting your pace drop for even an instant will lose you the race.

Tateishi won with a margin of nine seconds over the competitor in second place.

What skills do you need to climb the stairs quickly?

Whether the course is long or short, you have to consider the energy you need

to complete the entire race and calculate the right pacing accordingly.

Many female competitors are good at long distance running,

and as this course lasts around 10 minutes, it should suit them well.

And in order to pick up speed, it's how you use the handrails and turn on the landings.

Your technique in these areas is key.

"But you can't just train anywhere, right?"

In Japan, we don't have any buildings where we can practice, so instead I climb up the staircase of a certain shrine.

In winter, I might run up and down 20 times and just 10 times immediately before the race.

This is where Tateishi trains with Watanabe, on a staircase of 230 steps.

She strives to improve her muscular strength and climbing technique.

She has learned much from Watanabe Ryoji, and she works to make his techniques her own.

If you rush from the very start, you'll exhaust yourself.

So, focus your mind on the soles of your feet and relax.

Kicking off the steps more gently softens the impact on your feet.

Training with Watanabe has been an important part of her progress.

High intensity training with a male athlete improves my performance.

It's an effective way of using my time.

At 634 meters, Tokyo Skytree is the world's highest tower.

In September 2022, Tateishi joined the daunting 2,552-step climb up Skytree.

She won the race with an incredible 41 second margin over the athlete in second place.

Watanabe won the men's race in 15 minutes thirty-nine point five-eight seconds.

Last year I raced at Tokyo Skytree, and I found the staircase there easy to climb.

The steps vary in height, and the handrails are all different, too.

Every athlete has their own preference, but Skytree was great for me.

"And you won that race, right?"

"How were the steps and handrails different?"

In Europe, where people tend to be taller, the handrails are higher.

Asian athletes, who tend to be smaller, find it hard to grasp the high handrails and establish a good rhythm.

High steps are also problematic, particularly for women,

who have less muscular strength than the men, so higher steps make it hard to get into a good climbing rhythm.

Tateishi has a particular technique that she uses to conserve energy.

I try to lean forward.

However, if you look at the floor, it becomes harder to breathe, so I try to keep my head up.

All of the stairs have a handrail, so it's important to make effective use of it.

Firstly, I seize it with one hand.

You could use both, but using one hand opens up the chest and makes it easier to breathe.

So, when the going's good, I only use one hand.

The hand grabbing the handrail gets tired first.

So, when my arms start to ache, I use both.

The world's best Stairlicmbers are gathered here in Osaka.

With a packed field of rivals, can Tateishi Yuko win the 2023 World Championships,

Stairclimbing's most prestigious event?

Let's see how she got on.

In November 2023, a World Championship race was held in Osaka at the 300-meter-high Abeno Harukas.

The staircase has 1,610 steps.

It will take even elite male athletes around 10 minutes to reach the top.

Some of the world's finest competitors have gathered here today.

I have my eyes on a top runner from Finland.

And I'm also impressed by the Mongolian runner and the Bulgarian entrant.

Tateishi's biggest rival is Yoshizumi Yuri, winner of the previous World Championships.

She's a versatile athlete whose main sport is trail running.

Tateishi, who finished second last year,

is determined to beat Yoshizumi this time around, after winning several Stairclimbing races.

Yoshizumi's goal is to break her own course record and win the race,

but that record is about 1 minute faster than the time I recorded last year during the Japan circuit.

So, if she does break her record, I'm going to have to go an awful lot faster.

Having said that, I've done more Stairclimbing than her over this past year,

and I want to exploit that experience and do my best.

The World Championship event starts with the men's race.

Watanabe has already climbed up Abeno Harukas on six separate occasions.

The staircase is quite complex and some floors have very long landings.

These irregularities can disrupt a runner's rhythm.

A complex course means that, to climb fast, runners need to maintain their rhythm as well as their energy levels.

In the men's race, Watanabe is the first to reach the 60th floor.

He records a time of 8 minutes and fifty-three point six-one seconds,

winning the World Championships for the first time.

I've been training hard, so I was confident I'd win.

And it was that confidence that carried me all the way to the 60th floor.

The women's race was held immediately after the men's.

Tateishi starts in the middle of the front row, right next to rival Yoshizumi.

Tateishi is familiar with the course and plans to keep up a fast pace during the first half, to stay ahead of the field.

Many of the best runners are strong in the second half of the race.

So, I plan to go out quite quickly, gain some distance and hold that lead.

Tateishi reaches the 10th floor in first place after just 1 minute and 23 seconds.

But by the 20th floor, Yoshizumi has claimed the lead, pushing Tateishi back into second place.

Yoshizumi leads by just five seconds.

As the race progresses, Yoshizumi starts to pull further away from the rest of the field.

Tateishi appears to have gone out too quickly in the early stages of the race.

I knew that Yoshizumi's really strong during the latter half of the race, and that I needed to go hard early on.

But after 20 floors, my body wasn't moving the way I wanted it to.

By the halfway point, Tateishi is starting to fall behind.

The Finnish and Mongolian athletes overtake her,

dropping her to fourth position, 18 seconds behind the leader, Yoshizumi.

The race enters its final stages.

With her legs getting heavier, Tateishi just about manages to maintain fourth position.

Yoshizumi reaches the 60th and final floor in the lead.

And while she doesn't break her own course record, she successfully takes her second successive world title.

Tateishi approaches the finish line.

She valiantly holds on to fourth place.

Tateishi records a time of 11 minutes and 33 point three-six seconds,

losing out again to Yoshizumi, this time with a significant gap of more than one minute.

"You did good. There's always next time."

So, looking back on the World Championships, how was it?

I was really determined to become world champion,

but I knew that Yoshizumi's course record would be really hard for me to reach,

and that made it difficult for me to decide how to approach the race.

As I won here last year, I felt that I really had to go for it,

so I took a very aggressive approach, but in the end,

I went a little too fast too soon and that turned out to be fatal.

While she didn't get the result she wanted this time,

Tateishi believes that the sport of Stairclimbing is adding much to her life.

The other day, my son made a building out of toy blocks and said, "this is mom's job, right?"

"That's so sweet!"

I know, right?

"He gets it!"

I'm not a professional yet, and most people don't consider Stairclimbing to be my job.

So, my son was the first person to say that to me.

I decided to keep on running after having a child

when I saw how normal it was for many of the overseas athletes to carry on competing after giving birth,

and taking their children with them to competitions.

This race was a little too fast for me, and by the 20th floor, I was slowing down.

So, although I held on, I only finished in fourth.

My time wasn't that good, but I still think that as an elite athlete competing on the international stage,

making a fast start was the right choice.

Tateishi Yuko. Her performance here has given her much to reflect on.

But she's determined to resolve her issues, rebuild her confidence,

and continue to take on this unique sporting challenge.

Stairclimbing - where competitors stretch themselves to the limit to reach the top.

But Stairclimbing isn't just for elite athletes.

So, why not take your first Stairclimbing steps today?

Hi there. Now, who do you think is the strongest rikishi of all time?

I know everybody has a different opinion.

But in terms of winning percentage,

no one even comes close to this rikishi.

Futabayama holds the Grand Sumo record of 69 consecutive wins. But it's not him.

Yokozuna Hakuho won 45 top-division championships. Amazing! But it's not him either.

He is Raiden. Come on.

Now this is the Yokozuna Stone Monument.

Look at the names of all the past Yokozuna inscribed on the monument.

Now, Raiden wasn't a Yokozuna,

but his name is inscribed on the monument as an unparalleled rikishi due to his remarkable achievements.

The only rikishi who's had his name inscribed here even though he wasn't a Yokozuna,

is the 18th century legendary rikishi; Raiden Tame-emon.

197 centimeters in height and weighing 172 kilograms, he was exceptionally big for a rikishi of that time.

Raiden holds a career record of 254 wins and just 10 losses.

His winning percentage was 96.2 percent, in comparison to Futabayama at 80 percent, and Hakuho at 83 percent.

Raiden tops the list by far.

Raiden's remains are buried in four different graves in Japan.

Each place is closely related to the unmatched wrestler.

And one of them, is this Houdouji Temple in Tokyo.

Now this is Raiden's tomb.

Across the country, there are as many as four Raiden graves.

This seems to reflect people's desire to gain something from his almost superhuman power.

A large stone has been placed in front of the grave.

Raiden is said to have used it for training.

Legend has it that if you touch it, you can acquire power.

Give me power!

Raiden was born in Tomi City, Nagano Prefecture, about 180 kilometers northwest of Tokyo.

His home was recreated, and is now open to visitors.

Seki Kenji is an 8th generation descendant of Raiden.

Over the years, the family has kept the legend of Raiden alive.

Raiden was always expected to win.

He was banned from making offensive moves, because he would injure his opponents with his onslaughts.

It's said he was banned from a total of three offensive moves,

including face slapping and thrusting, because of his remarkable power.

Even so, he still overwhelmed other wrestlers.

There's a legend about him at the Takei Shrine, also in Nagano Prefecture.

This tabular stone weighs about 4 tons.

The story goes that Raiden carried the stone bridge that had straddled a river to preserve it at the shrine.

Now, here's the million-dollar question: Why did such a strong rikishi not make Yokozuna?

That's because back in the day, the rank didn't exist.

When the Yokozuna stone monument was erected,

people decided to inscribe Raiden's name due to his unparalleled strength and achievements.

Simply put, he was incomparable.

We've seen many strong rikishi over the years.

Raiden is well respected and very popular even to this day.

And that's because his incredible accomplishments still enthrall many people.