Ordinances (zhao 詔, zhaoshu 詔書) were in early imperial China proclamations by an emperor or answers to requests by high officials. They dealt with all matters not decided on by laws or regulations. They are a subtype of edicts and orders (zhaoling 詔令). Cai Yong's 蔡邕 (132-192) governance handbook Duduan 獨斷 explains zhaoshu as "explanations, instructions" (zhaogao 詔誥), and says they were but one form of edict, side by side with strategic orders (ceshu 策書), decrees (zhishu 制書), and exhortations (jieshu 戒書).
The term was introduced by the First Emperor of Qin 秦始皇 (r. 246-210 BCE) as a replacement for the word "order" (ling 令). Liu Xi 劉熙, author of the glossary Shiming 釋名, explains the word zhao by using the homophone words zhao 照 "to clarify" and zhao 昭 "clear", and says that zhao-type documents were used to clarify things and reasons in order to prevent people from breaking the law. These "instructional letters" (zhaoshu) were used to instruct high functionaries or to answer to their petitions and memorials, but also to announce important events like the passing away of an emperor or the accession to the throne.