In the Tang Ritsuryo system, the government's decision-making organization consisted of the Secretariat that planned and formulated policy by order of the emperor, the Chancellery that discussed the plan formulated by the Secretariat, and the Department of State Affairs that executed the policy approved by the Chancellery.
唐律令では、国政の意思決定機構は、天子の命を受けて政策を企画立案する中書省、中書の立案を審議する門下省、門下省が同意した政策を実行する尚書省から構成されていた。