TOKYO — Like sushi, Mount Fuji and kimonos, the ancient sport of sumo wrestling is a touchstone of traditional Japanese culture.
On Sunday, President Trump plans to attend the final match of an annual spring tournament in Tokyo, where he will present a custom-made trophy to the winner, drawing international attention to the country’s national sport.
The four-day presidential visit to Japan comes at a time when sumo, with its ritualized spectacle of oversize men grappling in carefully coifed topknots and loincloths, has come under intense scrutiny for discriminatory practices, hidebound traditions and bullying scandals.
Yet the sport also reflects a pivotal moment for Japanese society as it inches away from a deep-rooted insularity and opens to an increasing number of foreign workers.
Many traditions of sumo, whose origins can be traced to early Shinto rites and ceremonies conducted in eighth century imperial courts, have not changed in more than 200 years. But in at least one regard, the sport has been transformed in recent decades, as a growing number of its champions have come from abroad. Today, about a quarter of sumo’s top-ranked wrestlers are foreign-born.
More and more fans are also coming from abroad to enjoy sumo’s combination of brute force and nuanced psychological maneuvers, buoying sold-out tournaments, known as bashos, around the country.
Mr. Trump will be the first American president to present a trophy at a sumo tournament, although foreign ambassadors and other dignitaries often hand out special cups to the winning wrestlers.
Some critics in Japan are dismayed that the final bouts of the spring tournament are being turned into a diplomatic showcase for Prime Minister Shinzo Abe and Mr. Trump.
“Trump is taking a seat for Abe’s promotion,” said Shizuka Wada, the author of “A View of a Female Sumo Fan.” Ms. Wada said that she resented seeing her favorite sport being used to advance a political agenda.
“It looks ridiculous,” she said. “I just don’t want them to use sumo for such a purpose.”
For some, the agitation is intensified because Mr. Trump and his entourage will displace some fans who bought advance tickets and have now required special accommodations.
While fans with ringside seats typically sit on the floor on cushions atop traditional tatami straw mats, Mr. Trump at ringside will be given a low-backed chair, according to an official working on logistics for the visit who was not authorized to speak publicly. And while shoes are not allowed in the sumo ring, Mr. Trump will be given a pair of slippers to wear when he steps inside to award the trophy.
There is no official word yet on whether the trophy will bear Mr. Trump’s name and, if so, how big the lettering may be. A Foreign Ministry official said it would be a “president’s cup,” but declined to give further details.
Experts say there are likely to be a few other adjustments. Typically, when fans celebrate an upset victory, they fling their seat cushions, or zabuton, toward the ring. Such actions take place in spite of official prohibitions, but with Mr. Trump at ringside, Secret Service officers are likely to clamp down.
Minor disruptions aside, analysts of the longstanding alliance between the United States and Japan say that Mr. Abe chose shrewdly in extending the sumo invitation to Mr. Trump, who for decades appeared on television in the United States at professional wrestling extravaganzas.
“It kind of embodies the very muscular kind of power that he likes,” said Sheila A. Smith, a Japan expert at the Council on Foreign Relations. “It’s maybe a more comfortable and interesting setting for him than some of the more pomp-and-circumstance red carpet settings.”
The spring basho runs for two weeks, and there have already been some upsets. The final is likely to be a nail-biter, with the championship expected to come down to a battle between a Japanese wrestler and a top-ranked Mongolian wrestler, whose countrymen have dominated the sport for almost two decades.
Seasoned sumo watchers say the prominence of foreign-born wrestlers shows that the sport has in some ways been at the vanguard of Japan’s incremental globalization.
Sumo wrestlers from Hawaii came to Japan in the 1980s, and champions from Bulgaria, Georgia, Estonia and Mongolia followed. There has been some backlash, but for the most part, Japanese fans have embraced the new champions.
“Sumo, which is the most Japanese of sports, was under no pressure to do so, but opened its doors to foreign workers decades ago,” said John Gunning, an Irish-born, English-language sumo commentator on NHK, the public broadcaster, who represented Ireland in the world sumo championships.
“There might be an image of them being an old, stuffy, conservative organization, which is an accusation that has some merit,” said Mr. Gunning, who also writes a sumo column for The Japan Times. “But in general, they have led the way and shown Japan this is what can be done and the world doesn’t come to an end just because you let a few foreigners in.”
As Japan prepares to admit more foreign workers in the face of severe labor shortages, some analysts regard foreign-born sumo wrestlers as “model immigrants.”
“They work hard, master the language and are well adopted into the society,” said Satoshi Miyazaki, a linguist at Waseda University and author of “Why Do Foreign Sumo Wrestlers Speak Fluent Japanese?”
In other respects, sumo has been fiercely criticized for its outdated traditions. Last spring during an exhibition match in Kyoto, a referee shooed women out of a ring when they rushed to offer lifesaving measures to a politician who had collapsed while delivering a speech.
The incident set off a media firestorm about whether the sport was using its tradition of barring women from the ring as an excuse to reinforce gender discrimination. The Japan Sumo Association, which governs the sport, has committed only to studying the issue.
Sumo’s rigid rules and customs — wrestlers are not allowed to drive; about 90 percent of them are not paid; and younger apprentices are required to clean, cook and perform endless tasks for their elders — have created a culture in which hazing and bullying have led to some high-profile scandals. Allegations of match fixing and of ties to organized crime have also plagued the sport.
“Tradition is not an absolute value,” said Takayuki Harada, a professor of criminal psychology at the University of Tsukuba. “It should be changed. We need to raise awareness for human rights.”
Although sumo continues to garner a sizable fan base, some experts warn that could change if the sport does not modernize.
The sumo association “sits back as they are enjoying lots of fans,” said Takanobu Nakajima, a professor of economics at Keio University who served on an independent committee to review the governance of sumo after the match-rigging scandal was exposed. “But most of the fans are getting old. So can sumo survive in the future?”