A cash seal (; "Baochao" means "valuable money", "Yin" means "seal") is a type of seal used as an anti-counterfeiting measure on paper money. The cash seal first appeared during the Song dynasty in China.
The short name is Chao Yin (), and the full name is Seal of Baochao (), or Baochao Yinjian (). The name can also be simply translated as "money seal" or "note seal".
The economy of China during the Song dynasty outpaced the supply of traditional coinage, leading the government to issue paper money (Jiaozi (交åÂÂ)) to increase the money supply. Subsequently, a government department was created to manage cash affairs, with its responsibilities including producing and issuing cash, and combating counterfeiting. The cash seal was developed as an anti-counterfeiting measure; official government notes received a red, sometimes black or purple, stamp at their centres. This forced counterfeiters to attempt to replicate the seal, presumably leading to distinguishable lower quality stamps. Severe punishments, including the death penalty, were given to counterfeiters.
The Ming and Qing dynasties also stamped notes. The Ming government department responsible for cash affairs and the use of the cash seal was the Baochao Bureau ().
The use of cash seals is no longer restricted to governments. Seals or private individuals and organizations may be used in the same manner on private notes to represent the parties' trust, credit, or authority.
In the era of the Republic of China, these seal stamps could also be called Yinhang Yin (éÂÂè¡Âå°/é¶è¡Âå°; direct translation: the seal stamp of bank, or just "bank seal").
In Japan, ginkà Â-in (Japanese: éÂÂè¡Âå°) seals have similar functions.
In Singapore, a seal has been present in all Singapore dollar banknotes since its first series, bearing the chairman of the Monetary Authority of Singapore (MAS) or the Board of Commissioners of Currency, Singapore (BCCS).
In late imperial China: