- 丹书铁券 dānshūtiěquàn iron certificate(bound form) an iron certificate with red lettering granted by ancient emperors to high officials, ensuring immunity from certain crimes and punishments for generations; half was kept by the court and half by the official's family.
- 金书铁券 jīnshūtiěquàn iron certificatedecree granted by an emperor to a meritorious official, often exempting the recipient and their descendants from criminal prosecution; literally gold-inscribed iron certificate