What is the History and Usage of Chinese Seals (印章/Yin Zhang/Yin Chang: History and Usage)?
The Role of Chinese Seals for Authorization and Display of Privilege
If you have ever seen a work of Chinese art, you have probably noticed small, and sometimes large, red emblems interspersed through the work. These emblems may sometimes appear disruptive, but they are in fact integral to Chinese ideas of authorship and authentication. No work of Chinese calligraphy or painting is complete without the application of the author’s seal.
In China, Seals have been used for thousands of years to ensure the authenticity of important documents. In the Shang dynasty, important documents were transported in wooden containers capped with clay. In order to ensure that the documents were not tampered with in transport, a simple seal, likely with a clan symbol, was applied to the clay before it dried. Later, with the emergence of paper documents, seals bearing more complex characters would proclaim the authenticity of a document. A result of this was that simply owning a seal would be a marker of one’s political authority. As seals became part of the official apparatus of the state, esteemed individuals began to commission seals of a more fanciful nature. Auspicious sayings were engraved on seals so that, in more personal correspondence, the literati class could ‘authenticate’ their good wishes toward the recipient of a letter or poem.
Even today, seals form an important part of Chinese culture. All government institutions use seals to authorize their documents. In many cases, the presence of a seal is even more persuasive than a signature: Chinese citizens will often use a name seal to conduct business, using them to open bank accounts or sign contracts much in the same way that a Westerner would apply a signature.
The General Usage of Seals in Chinese Brush Painting and Calligraphy
With such a premium being placed on seals for the authentication of official documents, it should come as no surprise that seals have also come to play a role in the art forms of the literati. Similar to the Western practice of having an artist sign their works, Chinese calligraphers and artists will always apply a name seal in order to complete their work. If there is an inscription, the seal will follow it. In addition, a ‘leisure seal’, often with an auspicious saying, can be used to provide balance with the name seal. Such seals can come at the beginning of a work or indeed just about anywhere the artist fancies. However, it should be noted that all seals are applied after the brushwork has been finished, and are placed with deference to the over-arching rhythms and movements of the work itself. Artists may also choose to apply a studio seal, with the name of their workshop, as an extra level of authentication or ornament.
As the history of Chinese art has progressed, many famous works have been repeatedly lost and found. Likewise, from at least the Tang dynasty, forgers have attempted to pass off works for far more than they are actually worth. As a result, connoisseurs have occasionally been asked to apply their own seals to important works in order to certify their authenticity. This practice of adding new seals was also carried out by emperors wishing to celebrate or promote certain works. In some cases, works of great antiquity have been all but obscured by continuous seal application. Nevertheless, the more seals a work has, the more it is likely to cost on the open market: a work’s standing in the history of Chinese art is often inscribed directly on its surface, for all to see. 
