Speed Sprint, a Jump Rope category where competitors rotate ropes with remarkable speed.

With many its other categories, Jump Rope is growing in popularity around the world.

A Japanese competitor recently won the 2023 World Championships.

Inaba Kaiya.

Renowned for his world-leading techniques, he's going to open the box on Japan's current success in the sport.

I'm holding a rope used in Jump Rope competitions, and as you can see, it's made of wire.

I've never seen a rope like this before.

In Japan, jumping rope is extremely popular among children.

In recent years, this simple pastime has evolved into a dynamic urban sport,

which is growing in popularity around the world.

Some of the top international competitors are Japanese.

Let's take a look at the dedication they need to put in to master this exciting sport.

Jump Rope has many different forms and disciplines like Single Rope, and the Double Dutch competition.

Today, we're going to focus on Single Rope, which is further divided into three major individual categories.

The first is Speed Sprint,

which requires competitors to jump the rope as many times as possible in 30 seconds.

The second is Speed Endurance, which extends that time to 3 minutes.

And the third category is Freestyle,

which sees competitors graded on difficulty and artistic expression.

The World Jump Rope Championships were held in the United States in July,

with 3,000 participants from more than 25 countries and territories taking part.

Inaba Kaiya reaches the final of the Single Rope Speed Sprint competition.

The six finalists face it off to see who can jump the most in 30 seconds.

Inaba is in the middle of the group.

The number of jumps is displayed in the upper righthand corner of the screen.

The count rises for each right-footed jump.

Inaba achieves a remarkable total of 112.

As this only includes right-footed jumps,

it means he's jumped a total of 224 times, which works out to 7.5 rope spins every second.

This impressive performance makes him the world number one.

Let's welcome a world champion in the Jump Rope Speed Sprint category, Inaba Kaiya.

That was awesome.

You're amazing. Thank you so much for joining us today.

Competitors in the Speed Sprint category use a rope made of wire.

"It's quite short!"

Yes, it is quite short.

Normally, a skipping rope comes up to your belly button or maybe your chest.

But the wire ropes are shorter, and only reach below the waist.

A shorter rope means that there is less rope to spin.

A longer rope is harder to control and heavier, so shorter and thinner is better.

You can see that Inaba constantly leans forward as he jumps.

Why did you bend down so much?

One reason is simply that the rope is very short.

Another reason is that I strike the ground quite heavily with my feet

so that they can spring back up into the air.

When you're doing movements like this,

what tends to happen is that your upper body starts to lean backwards, and your whole body follows.

That's why, I keep my balance by leaning forward to counteract my foot movements.

Can I give it a try with your wire rope?

It's like kids' jump rope!

Here I go!

It's short!

"It's short! It's too hard!"

For many years, Inaba Kaiya has been one of Japan's foremost jumpers.

Why has he been able to stay on top of his game for so long?

We see what lies behind his remarkable abilities.

In 2016, when Inaba Kaiya was just 17 years old, he took part in the All Japan Championships.

He won the Individual overall competition, to become Japan champion.

He went on to dominate the competition for six consecutive years.

However, in December 2022, he missed out on his seventh consecutive title.

We can see that he was starting to rotate slightly to the left.

He's drifting in one direction with poor lateral balance.

This is caused by Inaba's tendency to lower the right half of his body further down than his left.

So, how do jumpers maintain their balance for their 30-second performances?

Inaba explains how his arms, feet and head work during a competition.

First let's take a look at his feet.

Notice that he lands on the front of his feet, lifting them back up before his heels hit the floor.

I try to spend as much time as possible in the air, bouncing back up quickly.

It's better to spend less time in contact with the floor and more time jumping.

I can see that contact with my left foot is longer.

Inaba's left leg is not quite as muscular as his right.

This means it takes him longer to lift his left foot up off the floor.

So, how does Inaba use his hands as he spins the rope?

As I bring my left hand back up, it feels as if my wrist is too slow.

In my mind, I imagine how I'm moving my hands up and down.

I'm not doing anything wrong, but it's just that my right hand is moving surprisingly more smoothly.

Inaba now takes a closer look at the position of his head.

Even when jumping at extremely high speeds, his head stays almost completely still.

I try to make my breaths as shallow as possible.

If you breathe heavily, your head moves which interrupts your rhythm.

With only 30 seconds to perform, error is not an option.

Inaba focuses closely on his muscular control.

Over the 30 seconds, I start by counting the rotations.

For the first 20 seconds I keep my usual form.

For the final 10 seconds or so, I try to switch things up so that I can use different muscles.

Using different muscle groups helps me maintain the same tempo.

Inaba's ideal form ensures his right and left side are symmetrical.

He also aims to maintain maximum speed throughout the 30 seconds.

To make that possible, he has some unique practice methods.

I try to gauge how my upper body and arms are feeling, my overall condition.

"How's it going today?"

Not so great, actually.

Inaba also uses a metronome when he trains.

He starts off at a speed of 100 beats per minute.

He moves his right foot in time to the rhythm

while looking to maintain a good overall left-right balance.

Sometimes the position and angle of my arms are incorrect,

so I use the metronome to improve my performance.

Once he's got his balance right, Inaba starts using the wire rope to simulate competition conditions.

Inaba continues to jump rope for longer periods,

making sure to maintain his balance, and forcing his body to remember the rhythm.

He jumps faster and faster as he gradually ups the tempo.

After taking a little rest, I'll start practicing at 260 beats per minute.

Inaba tries to skip at this speed for as long as possible, pushing his own limits.

He trains like this for between two and four hours every day.

That's it. I'm not doing so great today.

Disappointing.

You've only got 30 seconds, so you can't afford any mistakes.

With all that pressure, what's your mental approach to competition?

I do my best to relax and enjoy the occasion.

I'm out there in front of everyone.

I try to think positive and go into each competition determined to have fun.

Inaba took part in the 2023 World Championships.

It's evident that his lateral balance has improved as he managed to keep skipping on the same spot.

The honing of his training to understand his own weaknesses has the desired result:

Inaba becomes World Champion!

What are your goals for the future as an elite jumper?

My next target is to be first, in all three Single Rope disciplines, Speed Sprint, Speed Endurance, and Freestyle.

I want to be the best.

While Inaba Kaiya has been making a name for himself in international competition,

Japanese juniors have also been making their mark.

One reason for the long-standing strength of Japanese jumpers is the cultural tradition of nawatobi.

Jumping rope is part of almost every Japanese childhood.

"Let's start jumping rope!"

In Japan, almost everyone has jumped rope at least once.

The origins of jumping rope in Japan date back to the 16th century.

It's said that western style skipping was imported from Germany in the late 19th century

and it later spread to all corners of Japan.

Jumping rope clubs have become popular.

And in May, Inaba taught children at this club which has around 30 members,

of mostly elementary and junior high school age.

Some of the club's members also perform on the world stage.

Sato Ayumu, age 15, is the world junior Speed Sprint champion.

I started Jump Rope around the 5th grade of elementary school.

And the more you practice, the better you get, there's a sense of achievement.

That's what I love about it.

Nishizawa Sakura is 14.

She came fourth in the individual Freestyle category at the World Juniors,

and is a member of the World Championship-winning team.

I love it when I can beat my personal best or learn a new trick.

At the 2023 World Championships, members of the club won a total of five gold medals in individual and team competitions.

This is the club's chairman, Nishizawa Naoyuki.

Jumping rope isn't as flamboyant as other sports.

Working hard at something to improve yourself actually isn't so glamorous

and I think it matches the nature of the Japanese people.

Next year, the Asian Championships will be held in Japan, and then the Worlds the year after that.

So, I hope that many members of this club can represent Japan and win gold at those events.

The IJRU, the International Jump Rope Union, is hoping to see the sport at the Olympics.

Perhaps some of today's junior athletes will go on to become Olympians.

Inaba also took up jumping rope at a young age.

When I was in kindergarten, we played jumping rope at school;

that was when I tried it for the first time.

I remember being able to do a double under.

"In kindergarten?"

No. No way!

All the other kids used to flatter me and call me "Professor Jumping Rope."

I took to it right from the start and I've never looked back.

Inaba started going to a jumping rope club from the age of seven, and began to pick up more skills,

before becoming Japan Champion at the age of 17.

"Let's get started! Do your best!"

Inaba currently teaches jumping rope twice a week,

hoping to pass on both his technical skills and love for the sport.

"Bring the rope forward, like this."

"That's it."

"Well done."

"It's fun!"

"What's your goal?"

"60 jumps in 30 seconds."

"To do a quadruple under!"

"What did you think of Mr. Inaba?"

"He's amazing!"

Jump Rope can be done anywhere; all you need is a rope.

And there's a whole host of tricks and skills to learn.

Inaba Kaiya hopes that as many people as possible will discover the sport and enjoy its benefits.

I hope that everyone interested in jumping rope will find different ways to enjoy it,

develop their own style, and just have a good time.

You can enjoy competitions, you can combine Jump Rope and dance, or Jump Rope and gymnastics or acrobatics.

The possibilities are endless.

It's not only about competition.

There are just so many options to experience.

In Japan, nawatobi or jumping rope has always been a popular pastime.

Jump Rope's humble foundations have evolved into an exciting urban sport with complex and technical skills.

One day, perhaps we'll see Jump Rope in the Olympics,

and more people will get the chance to appreciate the incredible talent of the jumpers

who have done so well at the World Championships.

Sumo's dohyo ring is constructed solely from dirt.

It withstands the fierce battles of imposing rikishi over the 15 days of a grand tournament.

Today, we'll show you how the dirt is made.

I'm going to visit the place where the dirt that is used to make the dohyo, is actually made.

So come along with me.

This company is located about 50 kilometers northwest of Tokyo.

It supplies the dirt for all 6 of the yearly Sumo tournaments.

It's called Hon-arakida; a perfect mixture of clay-like dirt and sand.

But the dirt collected from the riverbanks is not instantly suitable for use.

All right. You see that dirt piled up here?

I've invited an expert to explain to me the whole process.

Hello. He is the expert.

Uchida Hideaki is a soil sommelier.

"How long does it take to prepare
the dirt before you ship it?"

Natural dirt contains lumps.

So, we need to make it finer.

We dry the soil to loosen the lumps little by little.

It takes about one year to complete the process.

Over a year, Uchida and his co-workers repeatedly plow the soil to loosen the lumps.

This process also dries out any moisture the dirt may have.

Weeds and other impurities must also be removed.

It's time for the finishing touch.

After a year of drying the dirt, it will be moistened once more.

This is to make it easier for the dirt to solidify.

However, the amount of water added requires much consideration.

When it's cold during the winter months, between November and January, too much water would freeze the dirt.

But during the summer, the water evaporates quickly.

In such cases, we add a little more water.

"So, the amount of water is different
depending on the season?"

That's right.

Water is applied to the dirt and is left for half a day to filter through.

Please touch it.

"Wow, it's so different now."

If you squeeze it gently,

you can shape it in your hand like a rice ball.

At this consistency, it's the best condition.

At this consistency, you can construct a Sumo ring that won't collapse.

If we're not careful in this final phase,

we won't be able to create a good dohyo, which endangers the rikishi.

It's our job to prevent that, especially during a 15-day Grand Tournament.

Finally, the dirt is packed into bags.

To build one dohyo, 40 to 45 tons of dirt are needed.

The painstaking process of making dirt suitable for a dohyo...

But it enables the rikishi to fight in a safe and secure environment.

The fine quality of the dirt is what enables the dohyo

to remain in perfect condition for entire 15 days of a grand tournament.

The dohyo made with this dirt is very popular among the rikishi,

because they know that they'll be competing on a very splendid battleground.