// 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 surprised by 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."
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.
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." //
We just leave our filth behind for some poor sap in minimum wage to clean up after us. A cultural thing.