I'm wondering how a 15 year old's school in Japan would be like. I've looked online for this stuff, but it's hard to find. If anyone could help, it'll be appreciated.

Stuff I want to know:
-scheduling (when does school start, break, end?)
-extracurricular stuff (what kind of stuff do they have there? How are sports run?)
-how much homework they have and what kind of hw it is (reports? projects? or just tons of practice problems?)
-punishments for tardies? discipline?
-grade system, level of competition
-juku? who needs to go?

Plus-- do 15 year olds usually have cellphones in Japan?