ARLINGTON, Texas - Determined to turn the stands blue for Japan's World Cup knockout showdown with Brazil on Monday, Japanese fans are ready with a massive stock of double-duty blue plastic bags -- for cheering on Samurai Blue and cleaning up litter afterward.

During Japan's final group-stage match against Sweden last Thursday at Dallas Stadium, a section of the stands turned blue as fans waved air-filled bags and cheered when the players entered the pitch.

Masaya Fukumori, 38, a longtime fan of the Japan national team, recalled that fans started bringing the bags at the 1998 France tournament after supporters urged each other to "make the stands as blue as possible." Fans have also used them at Olympic football and other events since the 2014 Brazil World Cup.

"We brought them for cheering, but it's great that it naturally leads to spontaneous efforts to pick up litter," Fukumori said.

Major hotel chain APA Hotel Co., a Japan Football Association national team partner, produced the bags for the ongoing tournament.

Volunteer fans then packed several hundred each in their luggage from Japan -- some 15,000 bags in total -- and handed them out at match venues.

Ahead of the Brazil match for a place in the last 16, Fukumori said, "With the blue bags in hand, I hope fans will cheer for Japan with all their hearts."

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