So it seems like violin is not that common in middle schools in Japan. In this chapter, a classmate of Aono-kun said that the only one playing violin at this school is Aono.
Aono is the son of a world-class violinist and he and his mom haven't moved out of the house since the divorce. Famous musicians often live in big cities for obvious reasons. I assume Aono-kun lives in a big city. So it is strange to hear that there's only one kid in a middle school who plays violin.
In a later chapter, a high school orchestra member mentioned that most of the second-violin players are beginners, which means they've never played violin before joining the orchestra.
It seems like brass instruments are more common than violins, or even string instruments in general. I wonder what's the reason behind it. I went to primary school decades ago in a country that is still quite primitive in classical music, and there was a senior at my school playing the violin.
Occasionally, I hear about acquaintances with kids learning the violin. But I didn't know anything about brass instruments until I watched Hibike Euphonium.