During the Manchu-led Qing dynasty, an emperor would write an edict to select one of his sons in secret. An emperor could have numerous sons by women of various ranks, so the heir might not be obvious until it was announced.
In the context of the Qing dynasty under Manchu rule, an emperor would issue a private statement to designate one of his sons as the next ruler. This process was complex due to the fact that emperors could have multiple sons from different social classes, making it difficult to predict who would succeed until the official announcement.