Not many athletic disciplines can hold spectators spellbound through 45 minutes of tradition before the opening contest is even determined.
Yet the detailed ceremonies unfolding in a small clay ring - mostly preserved for hundreds of years - managed to do just that.
This multi-day tournament at the Royal Albert Hall features four dozen top-tier sumo wrestlers showcasing a sport whose first mention dates back to the first century BC.
London's historic performance space has been utterly transformed, complete with a six-tonne Japanese temple roof hanging above the ring.
It is here the athletes, known as rikishi, perform their leg stomps to banish negative energies, and where they applaud to get the attention of the deities.
Above all this historical practice, a giant, revolving LED screen - that appears natural at an American basketball game - offers the crowd all the data and video they could want.
For one dedicated fan, it was a "unexpected footage" that first caught her attention a couple of years ago.
This was rapidly enhanced by the discovery of dedicated YouTube channels for rikishi houses, where athletes reside and practice, waking up early to train, followed by a nutritious chankonabe and then an daytime sleep - all in the service of gaining weight.
Another couple discovered sumo through a conventional method: a trip to Japan six years ago.
"We saw it as a very touristy activity, but we actually developed passion for the sport," says Julia.
"After that, we tried to locate groups, materials, just to deepen our understanding about it," the other fan explains.
Traveling to Asia is typically the sole method to see a top-flight sumo tournament.
This current tournament marks only the second instance the tournament has visited the city - the initial occasion was in the early nineties.
Even going to Japan isn't a guarantee of obtaining admission, with current times seeing fully attended competitions.
For many attendees, the UK competition represents the premier chance they have seen live sumo - and it exceeds expectations.
"Watching nearby, you get a understanding of quickness and the strength which you can't experience on TV," explains an attendee. "Their stature is remarkable."
To succeed, one competitor needs to move the other man off the clay or to the floor using brute strength.
The majority use one of dual approaches to succeed in this, often in moments - thrusting, or grappling.
Either way, the impact of the two rikishi meeting in the initial contact of the match echoes around the hall.
The cushions right next to the competition area are of course extremely sought-after - but also, somewhat dangerous.
During one specific contest, a tall wrestler fell into the crowd - perhaps making those in slightly cheaper seats experience comfort.
Of course, the size of the athletes is one of the first things most people think of when they think of sumo.
The hall's organizers revealed they "needed to find and buy new chairs which can take up to 200kg in weight."
But sumo - for all its popular tournaments - is not without its challenges behind the scenes.
Perhaps the demanding existence of a rikishi doesn't look as attractive as it once might have.
Its following among youth in Japan is also being competed with by other sports, while Japan's decreasing numbers will create further complications.
Not that any of this has concerned enthusiasts in London.
"Seeing all this tradition and practice that is part of sumo is especially significant," fan Sian says. "Today, watching it in person, you experience being you are more involved."
For other dedicated followers, the excitement "created amazing experiences" - as did encountering the other fans.
"Leaving a particularly focused online community and being able to witness multiple sumo fans directly and being able to speak to other people who are similarly enthusiastic as we are - it was completely valuable."
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