The Official Seal Of The Tang Dynasty Used Sputum Research

China has a long history of seal in the field of application and art, which is also the general term of office seal, personal seal, painting and calligraphy seal, connoisseur seal, portrait seal and other kinds of seals. Due to the limitation of amount, the research on the office seals of Tang Dynasty is much less than ones of Qin and Han. The research on that is still week and needs be spread in both breadth and depth, such as the identification standards, the origin and trend of the seal writing style, the connotation and external manifestations of the seal system. In this paper, we start the research from seal character in Tang official seal. Then we find the connection of them from the material of other character application fields and carriers.The key is the compare and research of the official seal script, the Zhuan Shu Qian Zi Wen of DunHuang, the inscription and top part of tablet, the seal character of the inscription on the memorial tablet in Tang Dynasty. The feature and influence factors of the usage of seal character in Tang Official seal are demonstrated, and the origin and trend of the character style are concluded and summarized.This paper is divided into three parts:In part 1, the feature of seal character in Tang official seal was specifically analyzed. We defined the concept of seal characters and book seal, and explain the difference of the art standard between seal character and book seal.Then, the official seal before Tang was studied, to find the origin of Tang official seal from the seal characters and book seal in previous dynasty.From this origin, we derive the causes and trend of seal characters in Tang official seal, and point out the situation that the seal character and book seal character are different in Tang official seal.Then with the form of table, we compared the Tang official seal characters, DunHuang Zhuan shu Qian Zi Wen, the inscription and top part of tablet, the seal character of the inscription on the memorial tablet in Tang Dynasty. The evolution trend of characters in Tang official seal was found. And with the specific analysis on the characters in table, we summarized the feature in the use of seal characters, the origin and trend of the character in Tang official seal.In part 2, we summarized the influence factor in the use of Tang official seal character from 3 aspects, namely the shape, material, crafts and system of Tang official seal, the style and feature of Tang seal character, and the social and environmental factors. The craftsmanship, the feature of Tang seal characters and the social aesthetic factors are particularly demonstrated for their key influence on Tang official seal.In part 3, based on the feature and origin of seal characters in Tang official seal, we analyzed the role that Tang official seal play in the development of seal, generalizing its historical status and the influence on the future. Since Sui and Tang Dynasty, the development of official had turn into a new period. The official seal in Song and after dynasty are casually developed and evolution on the basis of the inheritance of Tang official seal. It had a profound impact on the history of Chinese seal, and its east spread also impact Japanese seal significantly. Therefore, Tang official seal has very important and profound impact on the later development.