"It's not just part of the football culture but part of Japanese culture," Japan-based football journalist Scott McIntyre told the BBC. He is in Russia following the team and was not at all by surprised the somewhat different nature of Samurai Blue fans.
"You often hear people say that football is a reflection of culture. An important aspect of Japanese society is making sure that everything is absolutely clean and that's the case in all sporting events and certainly also in football."
A habit built from childhood
It is something that comes as a surprise to many foreigners attending matches in Japan.
"They might leave a bottle or some kind of food package on the ground and then it's often the case that people get tapped on the shoulder by Japanese people indicating they should clean up or take it home but can't leave it there," Mr McIntyre says.
Japan fans certainly know how to celebrate
It's a habit drilled into Japanese people from early childhood.
"Cleaning up after football matches is an extension of basic behaviours that are taught in school, where the children clean their school classrooms and hallways," explains Scott North, professor of sociology at Osaka University.
"With constant reminders throughout childhood, these behaviours become habits for much of the population."
What do fans make of the fact that their post-match cleaning spree becomes a regular hit on social media? If anything, they're proud.
"In addition to their heightened consciousness of the need to be clean and to recycle, cleaning up at events like the World Cup is a way Japanese fans demonstrate pride in their way of life and share it with the rest of us," explains Prof North.
"What better place to make a statement about the need to care responsibly for the planet than the World Cup?" he adds.
It doesn't mean that there is any more or less passion, insists Mr McIntyre. It's simply that passion doesn't slip into neglect of basic rules of behaviour let alone violence.
"I know it may sounds bland and boring, but this is the reality of a country that's built on respect and politeness," he laughs. "And this simply extends to doing respectful things in football."
"I think it's a wonderful thing that the World Cup brings so many nations and people together and get to learn and exchange these kinds of things. That's the beauty of football."
Published: 2018-06-20 10:52:30