which represents education and training of a total duration of eighteen to twenty years, including nine to ten years of primary and lower secondary school, at least three or four years of apprenticeship training – alternatively two years of vocational upper secondary school and two years of apprenticeship training – leading to a trade or journeyman’s certificate, professional experience as a craftsman for at least four years, further theoretical craft studies for at least one year, and a one-year study programme in educational theory and practice.