Cultural festivals (Bunkasai) in Japan are annual home-style events held by most schools, from preschools to universities where their students display their artistic achievements (the school's members celebrate). People who wish to attend the school themselves or who are interested in the school can come to see what the work and atmosphere of the school is like. Parents may also want to see what kind of work their children have done. This festival is usually open to the public, especially in high schools and universities.
Originally, the school festival was a formal curriculum in primary and secondary education, and it was mandatory for children and students to participate.
*It's mandatory, that's why the principal must record which classes have not submitted a list, they will definitely be billed to collect it immediately. Even extracurricular activities are also required to enliven it.