All countries have used seals of one form or another in their history, and in many cultures it is a very ancient history. We are familiar in the Western tradition with the metal seals of the European aristocracy that were impressed into wax and formed a seal on a document certifying either its authenticity or that the document was unopened. In China the history of the seal is more than 3000 years old. In the Qin Dynasty, which is the dynasty just before the beginning of the Han, the emperor Qin Shi Huangdi created uniform standards in weights and measures, and in writing as well. As a consequence, the reading and writing of Chinese became uniform and therefore meaningful to all Chinese citizens.
The seals that were originally developed in the very early periods were seals with simple characters that would be impressed into clay or bronze objects. This process lasted through the early archaic periods of Chinese history. Official seals tended to be made of bronze, because the act of creating a bronze seal is far more time consuming and complex than carving a seal from other materials. The standardization of the script and the development of the bronze seal set a tradition in which financial, political, and legal documents could be attested very simply and visually. Paper was developed toward the end of the Han Dynasty, about 200 AD. At that point the seal would be added to the written document by impressing it into a red seal paste and then impressing that onto the paper. Apart from names and official titles, there were also pictorial seals and those featuring auspicious or poetic phrases. This has been the tradition for the last 2000 years, even to the present.
As time passed, the forms of seals changed as did the use of seals. The earliest seals tended to be flat and unornamented. They would have either simple holes to add a string for handling, or an arched knob-like protrusion on the back to be used as a handle for loading the paste and making the impression. As seals came to be used on paper, they evolved into a more vertically elongated format which made it easier to grasp. In the Tang and Song periods, there was an elaboration of these forms. Carvings of animal forms were added, such as the zodiac animals or the four spirit creatures (the dragon, tiger, phoenix, and tortoise). Later period pieces tend to have more of the images of the fu dog, or the Buddhist lion, carved at the top.
By the Yuan Dynasty, seal carving had joined the ranks of the four essential arts of the literati or scholar class; the other three arts being poetry, calligraphy, and painting. The use of shoushan stone (a type of soapstone) allowed scholars to carve their own seals without the elaborate methods and processes necessary for bronze. Although jade and other materials were used in older periods, these were not easy materials on which to create calligraphy, especially anything extensive. So the softer materials such as soapstone, bamboo, wood, ivory, buffalo horn, rhinoceros horn, and many other materials including ceramics, became the more popular medium for the creation of the seals.
The flourishing enthusiasm among the literati for seal carving also included seal appreciation in the form of seal collecting and the integration of seals into the composition of paintings and poetry. Seals expanded in expression to include the decorative carved finials as well as colophons. The colophons on the side of the seals contained information referring to the time, place, circumstance, or inspiration of the seal. Seals could also have the name of a particular studio of an artist, or the pavilion name of a scholar. It could even have a line of poetry from an early and ancient Chinese work that was highly revered and well known by the elite of China.
The visual format of the inscription itself can be created in two ways. One style is by carving away the negative areas of the calligraphy to create a raised line form that will take the seal paste and thereby register the intended calligraphy when it is impressed on paper. In the other way, the character lines were carved away and the negative spaces would be printed in the red seal paste. In this case, when the seal is impressed onto the paper it will have an overall red image with the lines of calligraphy appearing as white because the ink did not enter the incised area. It is to be remembered that when the characters are created through drawing or scratching on the bottom surface of the seal, they must be created in reverse so that when the seal is impressed with ink onto paper it will register in the correct reading form.
The difficulty in creating the seal is, in many cases, the creation of the overall look of the seal. The nature of the calligraphy, the choice of material being used, the color and shape of the material, all contribute to the success of the piece. The most important and respected aspect of the seal is in the composition of the Chinese characters within the chosen space. The most common form of the seal space is simply a square in which the characters can be arranged in a grid like fashion. However many of the seals have irregular shapes because of the nature of the material being used, such as stone or wood. That flat surface and the composition of the placement of the characters within the flat space are exceedingly important elements, as is the nature of the calligraphy itself.
The variety of materials used and the choices that the carver makes in terms of using the colors and shapes of the natural materials is also terribly important. It is in some sense similar to the carving of jade, in as much as the ultimate success of the object is dependent upon not only the craftsmanship and the overall artistic design of the object being created, but also in the sensitivity of the artist in using the various color and textural aspects of the materials.
The collections at the Shanghai Museum and the National Palace Museum in Taiwan are great treasures and evidence of the immense love and respect that the Chinese people have for a small but terribly important artwork such as the seal.