What do China's three running scripts stand for?

The world's first running script: Preface to Lanting (Wang Xizhi) Preface to Lanting, also known as Preface to Lanting Collection, Preface to He Lin, Preface to Zan and Zan Tie. The preface narrates the beauty of the landscape around Lanting and the joy of gathering, and expresses the author's feelings of impermanence of life and death. Preface to Lanting shows the highest realm of Wang Xizhi's calligraphy art, and the author's tolerance, phoenix spirit, mind and feelings are fully displayed in this work. The ancients said that Wang Xizhi's cursive script is like "the breeze comes out of the sleeve and the next month comes into my arms", which is a wonderful metaphor. The second running script in the world: A Manuscript for the Sacrifice of a Nephew (Yan Zhenqing) Because this manuscript was written in extreme grief and indignation, no matter whether it was written by hand or by ink, the words fluctuated with the calligrapher's emotions, which was purely a natural expression of spiritual and peacetime labor. This is rare in the whole history of calligraphy. The poem "Huangzhou Cold Food Poetry" (Su Shi), the third running script in the world, is desolate and melancholy, and calligraphy is produced in this mood and situation. Throughout the ups and downs, rapid and steady, incisively and vividly, in one go. Su Shi put the changes of artistic conception and emotion in his poems in the changes of stippling lines, either before or after, changing and changing, breaking with the trend, and being natural. Its words are also strange, big or small, sparse or dense, light or heavy, wide or narrow, uneven, arbitrary and strange, and varied. Because of the praise of many scholars, the world called Cold Food Sticker, Preface to Lanting by Wang Xizhi in the Eastern Jin Dynasty and Book of Sacrificing My Nephew by Yan Zhenqing in the Tang Dynasty, or simply called Cold Food Sticker the third running script in the world. Others compared the "three major running scripts in the world" and said: "Preface to Lanting" is the wind of Confucianism, "Post for Sacrificing Nephews" is the wind of the wise, and "Cold Food Post" is the wind of scholars. Both of them are equal, each leading the way, which can be called three milestones in the history of China calligraphy.