Fans of Japan with garbage bags for cleaning before a FIFA World Cup game between Japan and Costa Rica on November 27, 2022 in Doha, Qatar. —Marvin Ibo Guengoer–GES Sportfoto–Getty ImagesOn Jun. 11, the FIFA World Cup kicks off in Mexico City. The coming days will deliver an opening ceremony spectacle, dazzling goals, dubious VAR calls, a viral celebration dance, at least one penalty shootout that ends in tears, a managerial firing, and the lifting of the trophy at MetLife Stadium in New Jersey on Jul. 19. Forty-eight nations, 16 cities, a global television audience that will dwarf any other event on the calendar. The drama is guaranteed.There is one other absolute certainty, and it will play out post-game, not on the pitch but in the stands: The Japanese Cleanup. At every World Cup since their country’s debut in France in 1998, Japanese supporters have stayed behind after the final whistle, pulled out blue plastic bags, and worked the rows, picking up cups, wrappers, and discarded flags until their section looked the way they found it. The ritual has been performed in defeat as well as in victory. As a result, tens of millions of people worldwide who could not name a single Japanese player, nor recall watching the Samurai Blue take the field, can describe the scene.The players have joined in. After Japan’s stunning 2-1 win over Germany at Khalifa International Stadium in 2022, FIFA tweeted out a photograph of the Japanese dressing room: towels folded, water bottles lined up, floor swept. On the table sat eleven origami cranes, one for each player on the pitch, and a handwritten note that read “Thank you” in Japanese and Arabic. When Japan was eliminated by Croatia 12 days later, the players did it again. Some folks cite the Japanese proverb, “Tatsu tori ato wo nigosazu” (The departing bird does not leave the water muddy) to argue that this form of civility is a national trait. I am not an expert in Japanese culture. What I can tell you is that the cleanup routine is one of the most efficient soft-power campaigns of the 21st century, conducted without a single yen of government spending or a single strategy memo from the Japanese foreign ministry in Tokyo.The soft power of civilityCan something as abstract as civility be an instrument of soft power? Let us go to the source. Joseph Nye, the Harvard scholar who coined the term, defined it precisely: the ability to influence others through attraction rather than coercion or payment. The Japanese tidying ritual is doing exactly that. It is influencing others to follow suit. In Russia in 2018, on the very day Japan beat Colombia in Saransk, Senegalese fans at the Spartak Stadium in Moscow stayed behind after their team's 2-1 win over Poland and performed the Japanese Cleanup. The Argentine sports network TyC Sports posted the video, and it was viewed more than four million times. The pattern had jumped continents and confederations. Four years later in Qatar, the Moroccans joined in the ritual. After their team’s 2-0 upset of Belgium at Al Thumama Stadium, many fans stayed in the stands with blue bags and cleaned up. They had done the same after the team’s opening draw with Croatia. A Casablanca content creator named Saad Abid had organized the operation in advance, distributing trash bags at stadium entrances two hours before kickoff.The Japanese fans are bringing their habit to ever more stadiums: from last year’s Under-20 World Cup in Chile to last month’s Japan-England friendly at Wembley. “It’s one of our traditions,” Toshi Yoshizawa, who led the Chile cleanup, told the Associated Press. “We grew up with the teaching that we should leave a place cleaner than when we arrived.” This suggests the Japanese habit is learned in the school system, where children sweep their own classrooms, mop their own hallways and serve their own lunches. The o-soji, or cleaning time, is built into the school day, every day, from the age of six.The cleanup goes globalUntil the smartphone era, this was a localized phenomenon, a curious factoid in a guidebook to Japan. But these days civility, much like rudeness, can ride a stream of shares and retweets to the far corners of the world. If a president’s dire threats to annihilate a civilization can instantaneously go global, so too can videos of fans on their hands and knees, filling trash bags. Saad Abid, a Moroccan environmentalist and social media influencer, did not need to import o-soji into his country’s schools to organize a stadium cleanup in Doha; he needed only a phone, a stack of trash bags, and the example of others who had done it before him. Neither Senegal nor Morocco shares Japan’s specific civic infrastructure. They share, instead, the willingness to watch what others do and decide to do it too.Which brings us to the World Cup this summer. Japan is in Group F, opening against the Netherlands at Dallas Stadium on Jun.14 before heading to Monterrey to face Tunisia. Senegal is in Group I, drawn against France at MetLife on Jun. 16. Morocco opens against Brazil, also at MetLife, on Jun. 13. The three nations whose fans have already demonstrated the habit are all here, on this stage, in front of cameras.The question for the next six weeks is not whether this can spread, but how far. Will Tunisian supporters in Monterrey reach for trash bags alongside the Japanese? Will the French follow the Senegalese, and the Brazilians copy the Moroccans? Will American supporters do likewise in the 11 cities hosting World Cup games? I fervently hope so.The global public square has been getting coarser for years, and social media has played a big part in the deterioration. If you watch enough of it, you can begin to believe that decency is in retreat everywhere, that the floor is giving way. The evidence from the stadiums says otherwise. It says that civility can be contagious, that it does not require a particular kind of upbringing or culture to take root in a new place, and that it can be picked up by people at a stadium on a Saturday afternoon because they watched others do it on Instagram. That is, in a small way, a hopeful sign for the species in 2026.If even a handful of the 48 nations competing for the World Cup join the practice, the Japanese Cleanup will have completed its long migration into the universal grammar of the sport, alongside the Mexican wave. And whichever nation takes home the trophy, we will all be the winners.