In an unassuming Tokyo tower block sits the headquarters of a sport at a spiritual crossroads.
A stone's throw from the Japanese capital's space age domed baseball stadium, and in the shadow of a nearby theme park's roller coaster, is the Kodokan International Judo Center.
From the lobby, it appears like any of Tokyo's countless high-rise buildings. A sign for a caf- in the basement and a small merchandise stand offer little hint of what's above.
But an elevator ride to the second floor reveals the home of a sport with competitive and philosophical roots stretching back over 130 years.
It's this floor that is home to the Kodokan's library and museum, where writings and images from judo's history are displayed in glass cabinets to be studied and revered.
The curator of this collection is Noaki Murata, someone who has built his life around judo and who cherishes the values first preached by its founder Jigoro Kano in 1882.
"The ultimate goal is to put inside our mind two principles," explains Murata, who -- despite his 68 years -- boasts broad shoulders and a strong posture that speak to his past athletic prowess.
"The principle of maximum efficiency and the principle of mutual welfare and benefit, that's the spirit of judo."
The Kodokan is an eight-storey training mecca for aspiring and elite-level judokas willing to eat, sleep and breathe the sport. While not exactly modern, every inch of the building is pristine.
Spread between the fourth and sixth floors are male and female dojos, while the hostel on the third provides accommodation.
The eighth is home to a fully-equipped gymnasium, where large windows allow sunlight to pour over the wooden spectator seats and the blue and red judo mats. The Kodokan boasts over 1,100 such mats.
It's easy to see how an athlete can improve their strength and technique in such a place, but judo is about more than physical prowess.
What sets it apart from other sports, Murata believes, is its broader goal of self-improvement.
"We could take only the physical aspect of judo, it could be a competitive sport with some rules," he explains in deep, considered tones. "This is why judo can be a competitive sport in the Olympics.
"But we don't say this is fully judo, this is a part of judo. What is judo? I think something more spiritual."
And Murata is certainly someone who has founder deeper meaning and purpose through the sport.
A promising tennis player during his junior high school years in Tokyo, and a strong sumo wrestler, Murata was drawn to judo when he saw his friends practicing in the sports hall.
He joined a local club and, after a couple of months of training, was able to defeat his friends in a judo tournament organized by local schools.
Spurred on by this early success, Murata eventually put down his tennis racket and wholeheartedly pursued "the Gentle Way."
As a young man, he enjoyed how judo enhanced his natural strength. He aspired to be like Isao Inokuma -- a heavyweight gold medalist during the sport's first Olympic appearance at the Tokyo Games of 1964.
His dedication to the sport saw him advance to the elite level of eighth dan and led to his appointment at the Kodokan. The institute has sent him on coaching missions all over the world, including numerous stints as an instructor in Europe.
As well as increasing his strength and broadening his horizons, Murata credits judo with making him a more thoughtful person.
"Think and do, think and do." That's his mantra and something he repeats over and over again. To him, it perfectly illustrates how to succeed in judo and in life.
Make a plan. Execute. Make a new plan.
"I became a person who took time to think deeper than before judo," he explains. "Thinking how I should be better.
"When I don't succeed, I should consider again. Your personality changes ... and I'm very happy because of that. And still I keep the same idea. More active. More active. More active."
And it is the positive actions of dedicated individuals like Morata that have made judo a truly global sport.
A record 389 competitors from 136 countries qualified for the Rio 2016 Olympic Games, while figures from 2014 claim there are 28 millions judo practitioners around the world with eight million in Japan alone.
This global expansion has created judokas all over the world, with judo's inclusion in the Olympic program allowing youngsters to dream of winning sport's ultimate prize.
But while judokas of Murata's generation saw judo as both a sport and a way of life, the prospect of a gold medal and wider competitive success is now the overriding motivation for up and coming athletes.
"This is not bad," Murata insists. "But I think Jigoro Kano would be feeling very sad if all Japanese think of judo as a sport only."
The current custodians of Japanese judo are only too aware of the importance of success on the mat when the world championships and the Olympic Games arrive on Japanese soil in 2019 and 2020 respectively.
Kosei Inoue was an Olympic champion in 2000 as well as a three-time world champion between 1999 and 2003.
Now he is head coach of the Japanese men's team and responsible for maintaining his country's formidable record in global competition. Japan took home 12 judo medals from Rio, seven more than any other country.
"I believe that the more you win, the more you have to lose," Inoue told CNN at the 2017 World Championships in Budapest, where Japan dominated the medal table with eight golds.
"Japan has many good practitioners, but their journeys are just beginning.
"It is one thing to win just once, and quite another to continue winning. Fortunately, there is a very good environment for judo in Japan; there are many judokas coming up from high school and universities, so there is a surplus of very skilled and talented athletes.
"As for the 'golden generation' of Japanese judo, we will do everything in our power to make sure they are ready to perform at Tokyo 2020, but the process doesn't end there.
"Coaches, athletes and the All Japan Judo Federation will work together to win all competitions."
As part of the organizing committee for the Tokyo 2020 Games, Yasuhiro Yamashita is a Japanese Olympic legend banking on the current generation emulating his success.
And while both he and Inoue are keen to stress the importance of Jigoro Kano's teachings, the soul of judo may have to take a backseat while the pursuit of golden glory is placed center stage in the coming years.
"As a child, I watched Judo competition at the 1964 Tokyo Games on TV and I was deeply moved by their performances," says Yamashita, who claimed a gold medal at the 1984 Olympic Games and is a bona fide sporting icon in his homeland.
"I dreamed of stepping on top of the podium and singing the Japanese anthem. It was my lifelong goal -- realizing my dream at the Olympic games in Los Angeles was a very emotional moment."
"I fully trust Mr. Inoue as men's head coach and Mr. Masuchi as women's head coach to lead the team to a great success," he adds.
"Also, I sincerely wish that their performances will give the Japanese citizens hopes and dreams. As the President of the All Japan Judo Federation I will do everything in my power to have Japan host spectacular events in 2019 and 2020."
And while Inoue and Yamashita drive Japan's competitive ambitions, people like Murata make sure its soul is protected.
According to him, as judokas age and are forced to step away from top-level competition, they are able to embrace the sport's spiritual side.
And it is through the words and actions of coaches and former competitors that the deeper meaning of the sport is kept alive in young enthusiasts.
Reflecting on the relatively brief career of a sportsperson, Morata says: "The time not being an athlete is a lot longer than the time being an athlete."
And it is this second career that he embraces; an opportunity to keep alive the teachings of Jigoro Kano.
"That is the time for me to give them the true meaning of judo," he adds.
"I show them myself, I show myself to be a good man, showing the spirit of judo."