Eternal return — the concept that all events are destined to repeat themselves over and over for infinity — has been a recurrent theme in 21st-century American television.

From the constant refrain that “all of this has happened before, and all of it will happen again” on "Battlestar Galactica" to the Schopenhauer-esque pessimism as voiced by "True Detective" character Rust Cohle in his famous “Time is a flat circle” speech, the idea of life being part of an infinite loop is a popular one in modern Hollywood.

Sumo’s flat circle may be physical rather than temporal, but recent turnover in Japan’s national sport has evoked feelings of a similar kind.

While it may be a stretch to call the changes that have taken place over the past month a like-for-like generational shift, some significant names have shuffled off the stage, only to be replaced by rising talents with comparable backgrounds.

Former ozeki Tochinoshin was, of course, the biggest star to call it a day, but the departures of former Tottori Johoku High School graduates Ichinojo and Ishiura also means two of the most notable wrestlers of the past decade will no longer be on the banzuke sheet come July.

Ichinojo, like Tochinoshin, was a hulking former amateur, whose sheer physicality often overwhelmed more technically adept opponents.

Few rikishi in the past half century have burst onto the scene in quite as dramatic a fashion as the Arkhangai, Mongolia, native.

After steamrolling his way through the makushita and jūryō divisions, Ichinojo won 12 of his first 13 fights in the top tier before finally falling to yokozuna Hakuho, just missing out on what would have been a stunning and historic Emperor’s Cup win in his makuuchi debut.

Promoted to sumo’s third-highest rank immediately following that July 2014 tournament, sekiwake would turn out to be as far as Ichinojo would go over the following nine years, as back issues prevented him putting together the long stretches of high performance needed to reach ozeki.

When healthy and on form though, the Minato stable man was nigh on unstoppable, with only a perfect performance from Hakuho in March 2019 denying him a first championship.

With the legendary yokozuna out of the way, Ichinojo finally tasted glory in July last year, and following a juryo division-winning 14-1 effort in March 2023, he looked set for another run at the Emperor’s Cup this May, before a sudden and unexpected retirement.

In contrast to Ichinojo’s quick exit, Ishiura’s departure was more of a long goodbye.

The muscular former collegian hadn’t set foot in the ring in over 14 months before announcing he was calling time on his active career and taking up the Magaki elder name.

Despite a 22-bout win streak to start his professional career, a lack of size prevented Ishiura from excelling at the highest levels of the sport. A special prize-winning 10-5 performance in his top-division debut was the only time the Hakuho prodigy would achieve double digits in makuuchi.

From his ripped physique to his sponsorship by sports car maker McClaren, to the fact that he was only in ōzumo because Hakuho convinced him to turn pro rather than take part in an already arranged audition for the movie Wolverine, Ishiura was always a rikishi apart.

As Tochinoshin, Ichinojo and Ishiura exit the stage, new hopes are rising to take their places.

Ukraine native Shishi’s second straight 6-1 performance at the top end of the makushita division earned the 26-year-old promotion to jūryō, and the honor of become the first sekitori from his country.

It also ensures there will be a European presence in sumo’s second tier, with Georgia’s Tochinoshin being replaced by a rikishi from a near neighbor.

Though not young, Shishi doesn’t have a lot of sumo wear and tear, and should continue to improve and rise up the rankings. It’s common to see foreign rikishi, once freed from the duties and chores of the lower divisions and allowed to focus on their training, make a jump up in performance.

Miyagino Beya has a ready-made Ishiura replacement in the form of former collegiate star Keita Kawazoe.

Closer to their stablemate Enho in size, Kawazoe is smaller than either of his two seniors, but more accomplished and technically adept.

Despite standing just 166 centimeters tall, the Nihon University graduate defeated NFL hopeful Hidetora Hanada to claim the title of college yokozuna in 2021.

Kawazoe’s new sekitori status also comes with a new name. He will henceforth be known as Kiho, with the second of two characters in that shikona being the same as that of his stablemaster's former ring name.

He’s not the only one to make a change.

Kiribayama followed up a debut title in March with a solid 11-4 outing in May and as a result was elevated to the sport’s second-highest rank.

Sumo’s latest ozeki also gets a new (old) name to go along with his promotion: Kiribayama becomes Kirishima, taking on the former shikona of his stablemaster Michinoku.

To paraphrase "Battlestar Galactica," “All of these names, and rikishi types have been seen before, and all of them will be seen again."

The dohyō isn't sumo's only flat circle.