On the calligraphy theory, Guo Shangxian left an extremely precious "Inscription of Fangjianting" for later generations. This book reviews mostly use the way of comments, commenting on a writer or work and expounding his own comments. Some just get to the point in two or three sentences. He advocated that calligraphy should respect Gu Yan, and he commented that Ziyou's tablet was "between Hanyi and Zheng Gu, and the book in the early years of Tokyo was so wrong after Wei and Jin Dynasties". Another cloud said: "This book is jumping and throwing, which washes away the habits of the Tang people, but it is not dull, but a bit embarrassing." Guo Shangxian thinks that the calligraphy of Li Bei is "the first in Han Li, super elegant and elegant, if Qingyun is in the air, it is above Chen Shi, Yiying and Confucius Temple." Comment on Tang Gaozong's Calligraphy of Jinglong Guanzhong Ming. Since Wei and Jin Dynasties, Guo Shangxian admired calligraphy.
Different people have different views on Wang Xizhi's calligraphy collected by predecessors. When commenting on Wang Xizhi's calligraphy collected in Elegance, he thought: "Huairen's collection of calligraphy is a masterpiece through the ages, and its disease lies in the close connection of fonts, so it is Huairen's own luck to be suspicious." It is the law of the Tang dynasty to cover the circle neatly, and the Jin people have nothing to do with it. This monument is not as good as Huairen's, but the branches are a little sparse. " There is a difference between this monument and Huairen Collection, which is very insightful. Guo Shangxian has a keen eye and often goes straight to the point when commenting on books. When commenting on Su Lingzhi, he pointed out: "The cover of Su Lingzhi's book is from Xue Sitong, and the method is not enough." It is said that Li's calligraphy in the Tang Dynasty was good at "making it soar and taking advantage of the situation"; Comment on Zhang's calligraphy "Rebuilding the Temple Monument" is "getting closer and closer to nature by taking advantage of the situation" and "working hard for the times". It is also said that the Tang people have no round front, but this monument is taking advantage of the situation. "> Guo Shangxian highly praised Liu Gongquan's calligraphy. He pointed out:" Liu Shuxiang is convinced that his writing style is Gu Zhuo, which is no deeper than this. Good people think they are cheerful, while sick people think they are fragmented. Inscriptions and Fu □ are less than Da Shang Bei, but together they are bold and powerful. What a magical force at this time. "Ming people evaluate Peixiu's calligraphy better than Liu Gongquan's, and Guo Shangxian is unconvinced. He believes that Pei Xiu's calligraphy is mainly neat, while Liu Gongquan's is mainly round and blunt, and Pei Xiu will never surpass Liu Gongquan. It can be seen that his calligraphy evaluation method is mainly based on the ontology of calligraphy art, and it is not easy to deny calligraphy art based on personality.
Wang Duo was first a minister of the Ming Dynasty and then a courtier of the Qing Dynasty. A biography of the ministers of the two dynasties ruined his reputation, but Guo Shangxian had a unique eye and devoted himself to propaganda. He attached great importance to Wang Duo's calligraphy and was the first person to affirm Wang Duo's calligraphy. He said: "Looking at Zhushan Garden Post, you will know that Jin Meng (Wang Duo) has played a lot in antique law, and his ideas are the same as Zhu Xi (Shan Zhi)." He also said: "I have lived in Beijing for several years and often read Jin Meng's Guo Xiang Shu. This volume of cooperation (masterpiece) is lush and flourishing, with both the victory of two wells and the victory of the sky (both wonders of the world). Speaking of it, it is made of hair, and it is graceful in its later years and turns into a winding and obscure shape. There is no such wind. " He affirmed Wang Duo's calligraphy art and criticized Wang's calligraphy in his later years as inferior to that in his early years. The reason is that in his later years, Wang Duo didn't have the spirit of dying for his country as Huang Daozhou and Ni Yunlu did, nor did he have the state of mind of "being born without a door" as Fu Shan did. Wang Duo's sadness and depression poured on calligraphy, and he lost the blood of middle-aged Wang Feng. This comment is impressive and to the point. Wang Duo's calligraphy was first appraised by Guo Shangxian, and his reputation increased greatly behind him. Fu Shan is a doctor and an orphan. He vowed never to admit defeat. His calligraphy is a weed, emphasizing temperament and momentum. Guo said: "Mr. Wang is a first-rate figure in the early days of the founding of the People's Republic of China, and the world is vying to be separated from him. However, he is angry and rich in grass, and he is unique. After reading a post in his book, Lao Dong is a kind word. Mr. Zhi is not conceited about books and doesn't want to be known by his own name. " Liu Yong was known as the "Prime Minister of Thick Ink" in Qing Dynasty, and his calligraphy was thick and rich. Guo also commented on the cloud: "All the scholars in Jin, Tang, Yuan and Ming dynasties are quiet and should be clear, not easy to be big. The author's country confronts the DPRK, and only Mr. Shi An (Yong) can be the deputy speaker. "Although this comment is inevitably exaggerated, it also has some merits.