In a broad sense, gunyaku meant conscription which included the labor service that was imposed on the people; but in a narrow sense, gunyaku referred to a retainer's offering of military service to the lord in exchange for recognition and guarantee of ownership of the fief (debt) in the relationship of 'debts and service' in the feudal system.
軍役は広義には民衆に課せられる夫役のうちの兵役なども含まれるが、狭義には封建制度における「御恩と奉公」の関係において、知行地の安堵（御恩）と引き替えに主君に軍事的奉公を行うことである。