This code was enacted as the succeeding fundamental law code to Taiho Ritsuryo Code and functioned as the essential laws and ordinances that prescribed the political system of ancient Japan; however, the code began to reveal the contradictions against the actual social and economic conditions in the Heian period, and even though the Kyakushiki code (amendments and enforcement regulations of the Ritsuryo codes) was also enacted to support it, it had become a mere name by the mid Heian period at the latest.
大宝律令に続く律令として施行され、古代日本の政治体制を規定する根本法令として機能したが、平安時代に入ると現実の社会・経済状況と齟齬をきたし始め、平安時代には格式の制定などによってこれを補ってきたが、遅くとも平安中期までにほとんど形骸化した。