Kosoku are the regulations established by each school to guide the behavior of students. Each school determines its own kosoku, aimed at maintaining order in the school and ensuring a safe and appropriate learning environment. These rules may prescribe, for example, the time students should arrive, the dress code ¡Ô¢ªseifuku À©Éþ uniform¡Õ, customs and appropriate behavior in the school, and how to report absences, resignation from club activities, etc. Some may also include rules concerning hairstyles, prohibiting students from obtaining a driver's license, or engaging in part-time work. In some cases, students who violate the rules (such as getting their hair permed) or obtain a license without permission may be temporarily grounded, suspended, or even expelled from the school.
Depending on the school, these regulations may be decided upon by the teaching staff or through consultation among students, staff, and parents. Some schools have no kosoku.
The Ministry of Education, Culture, Sports, Science and Technology, which has jurisdiction over the schools, officially notified all the boards of education in 1991 of the need to actively review school kosoku, taking into consideration the current condition of their students, the views of parents, local conditions, and the changing times.