Formal term for a written edict issued by an emperor, especially in historical or official contexts.
The emperor issued an imperial edict.
The emperor issued an imperial edict on New Year's Day.
The people received an imperial edict from the emperor.
詔書 refers to the actual written document that records an imperial edict, whereas 勅 denotes the edict or command itself, spoken or written.
Used for written messages and official documents; for an imperial edict, this is the natural counter if counting copies/documents.
From Middle Chinese 詔書 (tsyeuH syo), a compound of 詔 'imperial decree' and 書 'writing, document'.