How to understand "Jin people respect rhyme, Tang people respect law, Song people respect meaning, Yuan, Ming and Tai"

This is a famous book theory mentioned by Liang Biao, a calligrapher in Qing Dynasty, in a book review post. It has been highly praised by later generations because of its highly accurate generalization of the artistic characteristics of calligraphy in these dynasties. "Jin people respect rhyme", that is to say, the calligraphy art of Wei, Jin and Southern Dynasties pays attention to grace and charm. At that time, calligraphy advocated "spirit first, form second", and most of them showed a style of appealing to both refined and popular tastes. Its representative is the calligraphy of the two kings. Yuan Ang commented on Wang Xizhi's book in the Book Review of Ancient and Modern Times: "If Xie Jia's son is not upright, it will be refreshing." Xiao Yan commented on Wang Xianzhi's book in "Comments on the Advantages and Disadvantages of Ancient and Modern Scholars": "No one can imitate it, such as Heshuo teenagers, and they all like it and can't bear it." (Note: Resistance is ability. The charm of Erwang's calligraphy art has unique artistic charm, which embodies the characteristics of the times of Jin Dynasty's calligraphy art. In other words, the general trend of calligraphy in the Tang Dynasty was to attach importance to statutes. Calligraphers in the Tang Dynasty summarized the previous calligraphy, standardized and refined the calligraphy structure and pen use. For example, there are Ou Yangxun's thirty-six methods and eight strategies, Tang Taizong's calligraphy tactics, Yan Zhenqing's Interpretation of the Twelve Meanings of Calligraphy, Zhang Huaiguan's Ten Methods of Using a Pen and Forbidden Sutra in Yutang, Jelly Lin's Four-character Stirrup Method, and the Eight Methods of Yongzi and Five-character Zhi, which are most admired by later generations. Therefore, the regular script in the Tang Dynasty showed a trend of equal size, flush from top to bottom and proper brushwork. Even the relatively free and romantic cursive script has gradually abandoned the brushwork of the Jin people with a pen on both sides, and pursued the pure Chinese pen. In the atmosphere of advocating statutes, there appeared a rigorous and strong "Tang Kai" and an uninhibited "wild grass", which reflected the pioneering spirit of the Tang Empire. "Song people value meaning", that is to say, calligraphy in Song Dynasty pursues interest rather than legalism. Su Shi said: "It is not surprising that poetry does not seek work and is innocent as my teacher." Huang Tingjian also said, "Old people can't write, so I don't choose pen and ink. When I meet paper, I write a book and the paper runs out. I don't care about clumsy work and people's products. " Miffy said, "Learning books must be interesting. It's good that he forgot everything. If you don't have a good reason to worry about it, you will not work. " Dongti also said: "Calligraphy is more important in brushwork. If you are confined to Buddhism and pass it on to the Tang Dynasty, you will never come to the ancients. " All these fully show that the calligraphers in Song Dynasty did not stick to the ancient laws, but advocated appropriate artistic ideas, which were fully reflected in their representative works, such as Su Shi's poems on cold food in Huangzhou, Huang Tingjian's poems on banquet and Mi Fei's poems on Hongxian. "Yuan, Ming and Shang" refers to the calligraphy fashion in Yuan and Ming Dynasties, which mainly focused on imitation and paid attention to glyphs. The trend of calligraphy entered the retro period in the Yuan and Ming Dynasties, and most literati followed the example of Jin people and sought seal cutting. Zhao Mengfu said: "It is not easy to use a pen through the ages." In other words, the structure of characters can change with the times, while the ancient brushwork should remain unchanged. Zhao Mengfu's thought is regarded as the golden rule, so most calligraphers in Yuan and Ming Dynasties used the brushwork of the Tang Dynasty to write the book "The Appearance of People in Wei and Jin Dynasties", which formed a general trend that calligraphy only focused on the deliberate improvement of glyphs. Of course, the concepts of respecting rhyme, law, meaning and state put forward by Liang Biao here mainly summarize the characteristics of calligraphy in these periods, not to say that rhyme, law, meaning and state in these periods are isolated, but not linked. For example, in the Tang Dynasty, which respected the law, there were also elegant works like Yan Zhenqing's "Manuscript for Sacrificing a Nephew". In the late Ming Dynasty, the calligraphy of Fu Shan, Wang Duo, Huang Daozhou, Ni and Ni can't be evaluated by "Shang Tai". Huang Tingjian's calligraphy in Song Dynasty not only has "meaning", but also emphasizes "rhyme". They just don't represent the mainstream of the times.