The structure of Chinese characters has very regular geometric and mathematical principles, and is fixed in Ouyang Qing's "JiuchengGong", so that "Jiuchenggong" can become the rules of the script.
Yan Zhenqing and Liu Gongquan's letters, simple rules can be easily learned!
It is worth noting that among these rules, there are also some subtle changes, such as the angle of the pen, the change of weight, and the subtle changes of the adjacent similar strokes (such as the three strokes of the "three", the method is similar, but the form is very different), resulting in the Jiucheng Palace full of techniques and spirits that are endlessly explored.
The general history of calligraphy comments that the brushwork and structure of "JiuchengGong" are the most rigorous, referring not only to the mathematical and geometric laws of the "Jiuchenggong" showing the calligraphy, but also because of the many subtle changes in the combination of strokes in the "Jiuchenggong". In contrast, Yan Zhenqing and Liu Gongquan's calligraphy is much more monotonous, although Yan and Liu are the most widely influential calligraphers in Chinese.
Yan Zhenqing and Liu Gongquan's calligraphy is the introductory font for children to learn enlightenment and beginners to learn "big characters", in addition to the clear image of the two of them loyal to the king and patriotism, the most important thing is that their calligraphy is relatively simple.
Simple rules and techniques can be easily learned and have a wide impact. The so-called "simple" here is also relative, although Yan Zhen's obscure calligraphy technique is not complicated, but so many outstanding calligraphers in history, there are few who can learn Yan Zhenqing well. The same is true of those who study Liu Gongquan, and few calligraphers can learn well.
This is why, in the achievements of the letter, it was not until Zhao Mengfu appeared that there was a fourth person who was recognized by everyone.
Carefully analyzed, I personally believe that in order to write a good letter, it is necessary to have a very precise instinct, and in the writing style and structure, it strictly conforms to the mathematical and geometric rules of the font.
This kind of rule seems simple, such as Yan Zhenqing's brushwork, it can be said to be monotonous, but it is extremely difficult to be patient, write the words so neatly, and not too ingenious.
In history, there are many calligraphers who were once famous, such as the Shen Du and Shen Cang brothers of the Ming Dynasty, who wrote neat and round calligraphy, and Ming Chengzu even required all those who took the imperial examination to write the same as the Shen brothers, and their influence could not be said to be far-reaching, but the calligraphy of the Shen brothers did not enter the ranks of the first-class calligraphers in the history of calligraphy, and their calligraphy was not even valued by posterity.
The fundamental reason is that the shen brothers' character structure is simpler, more in line with the mathematical proportions and geometric principles, but because it is too consistent, so the writing is equivalent to printing and reproduction, and the spirit of calligraphy is lost.
Since ancient times, books on the structure of Chinese characters have been full of sweat, but the rules that are constantly complicated and trivial have not actually enabled people who study calligraphy to truly grasp the spirit of Chinese character structure, so I do not recommend too much in-depth study of the rules set by the ancients, or excessive rigidity to abide by those rules, because those rules do not necessarily make sense.