For example, Dong Sibai put forward: Jin people admired Yun, Tang people advocated law, and Song people advocated meaning. You can explain their respective meanings, and then use this clue to comprehensively study the changes in the style of the book.
I find it very interesting. Do you write? Or do you need to study because of exams? Calligraphy is a method of writing, but it only needs people who study calligraphy to study it. Many people who study calligraphy theory do not study calligraphy...