Students usually belong to a specific class with a designated classroom in which they study together all subjects except those requiring special classroom facilities such as music or science. In this case, the word homu rumu (homeroom) is synonymous with kurasu (class).
In elementary schools, the homeroom teacher is responsible for teaching the majority of subjects to the homeroom class. In the upper elementary grades, however, other teachers may give specialized courses in specific subjects such as music or science. In junior and senior high schools, each class has a specific homeroom teacher, but classes are taught under the senkasei, the system in which each subject is taught by a teacher who specializes in that field. These teachers go to the students' homerooms to teach, following the lesson timetable.
In the morning, at the end of the day before leaving school, or during special periods within class time, each class has homeroom activities. The homeroom teacher or the nitchoku (class day-leaders) 《→nitchoku, han, kakari, toban 日直、班、係、当番 groups,class day-leaders, person in chage, person on duty》 make various announcements, and the class discusses issues related to school-wide or class activities or engages in preparations for special events.
The daihyo iinkai is a committee made up of representatives of each class and often forms the basis for the school's seitokai (student council), which is a student self-governing organization. 《→Seitokai 生徒会, student council》
The average number of students per class, which for several decades after World War II was around 50, was reduced to 40 in 1986 (45 in senior high schools).