Tracing back to the source, the Tang Dynasty should be said to have started from the Sui Dynasty. As Zong Baihua pointed out: "In the Sui and Tang Dynasties, the' divine power' in Jin people's calligraphy was condensed into' dharma'." After the Tang Dynasty leveled the heroes, the society became more and more prosperous and stable, and the ideological and academic field tried to correct the weakness since the Six Dynasties with orthodox Confucianism. The cultural differences between North and South should achieve harmony and unity under the new historical conditions, and the law of calligraphy's own development also requires it to be standardized under a specific historical background.
In the early Tang Dynasty, taking books as teaching, taking scholars from books, setting up doctors and setting up calligraphy all needed to find rules, legislate, establish rules and set an example. "Law" has become a standard under the advocacy of national policies. "Fa" was originally attached to regular script. In the early Tang Dynasty, due to the continuous efforts of Ou Yangxun and Chu Suiliang, regular script gradually became a popular new book style. The style of regular script is characterized by meticulous strokes, clear framework and proper instrument and law, which is convenient for discussing and summarizing laws, establishing a model form and popularizing.
At the same time, there are many theoretical works about "law" in the Tang Dynasty, and they tend to be systematic. Ou Yangxun's Eight Methods and Thirty-six Strategies, Li Shimin's brushwork, Zhang Huaiguan's Ten Techniques, Yutang's Forbidden Classics and Yan Zhenqing's Twelve Meanings all had a great influence on the development of calligraphy in the Tang Dynasty.
In fact, the most important thing in the respect for Wang Xizhi in the Tang Dynasty, especially the advocacy in the early Tang Dynasty, is the arrangement of techniques and theories, which provided the basis and norms for the trend of thought of respecting the law in the Tang Dynasty. Similarly, the cursive scripts of Zhang Xu and Huai Su are consistent and universal, but as far as Tang Kai is concerned, the requirements for law are particularly obvious. Through the development of Tang Kai, it is not difficult to see that the real aesthetic connotation of "law" lies in the unity of political reform and law-abiding.
To sum up, it can be seen that the prosperity of calligraphy in Tang Dynasty is inseparable from the influence of power. Thereby creating the characteristics of an era. This is unique in the history of calligraphy.