It's practised by tens of millions around the world but there's no doubt that judo's spiritual home is Japan, where the martial art was created and made its Olympic debut.

It will be among the sports most closely watched by home fans at the pandemic-delayed Tokyo Games, and is so deeply embedded in Japanese society it even has its own branch of medicine.

Japan dominate judo at the Games, having won 39 gold medals since it debuted at Tokyo 1964, more than the next four best countries combined.

Judo was born in Japan but is practised by millions around the world
Judo was born in Japan but is practised by millions around the world AFP / Yasuyoshi CHIBA

That's perhaps no surprise given judo's roots in Japan, where it was founded in 1882 by the revered Jigoro Kano, whose benevolent portrait gazes down on judoka at dojos around the world.

Born to a sake-brewing clan from the Kobe region, Kano combined different forms of jujitsu with his own ideas, including spiritual discipline, and believed judo's ultimate goal was to "strive for personal perfection" through discipline and training.

He named his martial art "judo" meaning "the gentle way", and saw it as a means to develop both body and mind.

A teacher by trade, Kano was passionate about sport in general, and led the push for Japan to make its first Olympic appearance at Stockholm in 1912.

The sport was founded by Jigoro Kano, a teacher with a passion for sport
The sport was founded by Jigoro Kano, a teacher with a passion for sport AFP / Yasuyoshi CHIBA

But judo didn't feature at the Games until Tokyo first hosted the Olympics in 1964.

In competition, judo is contested on a mat with the goal of scoring an "ippon" or full point, which ends a bout.

Ways to achieve this include pinning an opponent for 20 seconds or throwing them so they land on their back. Half-points called waza-ari can also be earned and add up.

Bouts at the Games will last four minutes, and the action is often fast-paced and highly physical.

Some in Japanese judo fear the sport is losing its shine in its birthplace
Some in Japanese judo fear the sport is losing its shine in its birthplace AFP / Yasuyoshi CHIBA

Hifumi Abe and Shohei Ono are hotly tipped in the men's competition while Japan also has women's stars in Uta Abe and Akira Sone.

An egalitarian spirit is viewed by some as a key part of judo. Winter training at judo's hallowed Kodokan centre in Tokyo is open to everyone, and women have practised the sport since it was founded.

The Olympic spotlight could renew interest in judo in Japan
The Olympic spotlight could renew interest in judo in Japan AFP / Yasuyoshi CHIBA

Indeed Kano told his early disciples that the more subtle form of the martial art practised by women at the time would be judo's "real legacy".

Competition in Japan only opened to women from 1978, however, and female judokas made their first fully fledged Olympic appearance in Barcelona in 1992.

The Kodokan is the sport's home, and in pre-pandemic times attracted enthusiasts from around the world.

It will serve as a training centre during the Games, with competition taking place at the famed Nippon Budokan, which has hosted everything from Olympic judo to concerts by The Beatles.

"It is not just a Japanese sport," an official from the Kokodan told AFP.

"Judo has blossomed as a global culture."

But some worry the martial art is losing its shine in its birthplace, including judoka Tadahiro Nomura, the only person ever to win three gold medals in judo.

"It's something that people (in Japan) just see as an Olympic event," he told AFP.

"As for how it's run, how it started, how it spread around the world, the essence of judo, what it can teach kids and so on -- all that has been kind of forgotten."

Kodokan officials said they are hoping that "superb performances and conduct" by judoka from around the world "will inspire children to feel that they too want to learn judo".

And Nomura thinks the Olympic spotlight could give the sport renewed vigour.

"People might think, 'Oh that athlete is great and cool and strong,'" he said.

"It can be an opportunity for people to get into judo. If there's a local dojo nearby, it's easy to go along and try it."

But he worries that dojos are closing and the sport is seen as increasingly inaccessible.

"It needs to be fun, or somewhere to learn etiquette, or something to do for your health," he said.

"I think if local dojos can meet the different needs of people... judo can recover a bit of its popularity."