Senior secondary education often refers to three years of high school (or called senior middle school) education, as from grade 10 to grade 12. Normally, students who have finished six years of primary education will continue three more years of academic study in middle schools as regulated by the Compulsory education law at the age of twelve. This is not compulsory for senior secondary education, where junior graduates may choose to continue a three-year academic education in academic high schools, which will eventually lead to university or to switch to a vocational course in vocational high schools.