These guys are from an after school cramming center (juku), where some students go to get extra study in subjects like math, science and English. On the day that my future students were coming to my school to take their entrance tests, they were standing outside our gate, cheering the kids on. (They also come by later to take notes on which of their kids entered the school, so that they can boast of how many of their students entered the schools that they wanted to).
And the bandannas don’t have to have the W on them…or be any particular color either. Just there.
It’s a common theme to wear bandannas to show that they have worked hard and will win, although never inside the school. But…sometimes you can seem cartoon drawings of children taking tests and wearing the bandannas as advertisements on snacks during early March. If I can find the older Koala no March cookies, you’d see what I mean.