It is said that when Chu Yuan-chang took the throne he feared he might be challenged by someone else who shared his "emperor's fate" and secretly ordered a search to be made for anyone with the same Eight Cyclical Characters as himself.
話說朱元璋當上皇帝後，為了怕天下還有同樣「皇帝命」的人會和他爭位，因此密令屬下搜訪和他八字相同的人。