ARLINGTON, Texas — The phrase “Don’t mess with Texas” is well known ’round these parts, but few people realize it had nothing to do with toughness when it was first concocted. The tagline was originally, of all things, an anti-littering campaign 40 years ago. Keep the Texas highways clean.The Texans behind that slogan would love the Japanese.After every game at this World Cup and in previous tournaments, many Japan fans have cleaned up all of their garbage on the way out of the stadium. It’s a tradition that started at their first World Cup in 1998 and has continued at other events like the Olympics. They’ve become internationally famous as the organized effort draws attention from host countries and their media.If you don’t think cleaning up after yourself is that heavy a lift, one security guard here at Dallas Stadium told The Athletic he’d never seen a section so spotless after Japan and the Netherlands played here last week. So when Japan came back to face Sweden on Thursday, I wanted to take part and see it up close.“It’s part of our nature to clean up after our mess,” said New York City-based Japan supporter Kayo Kita. “In school in Japan, we didn’t have a janitor, so the students have to clean up after themselves. It’s our duty to do it. In Shintoism (a Japanese religion), we all believe every object has a spirit, so we have to respect them. Even this chair.”(The Athletic/Chris Vannini)To aid the cleanup, the Nippon Ultras supporters group brings 3,000 blue plastic bags to every match, laying them on seats and handing them out to anyone who wants one, including, on this occasion, an intrigued Argentina fan.On the bags are directions written in Japanese: Inflate the bag and use it to cheer before players take the pitch. Lower the bag when players line up. Don’t bother anyone with it. Be careful around children. And dispose of it in accordance with local rules.