Yu Yonghe's nine-year calligraphy classic is Preface to Lanting, written by Wang Xizhi, a calligrapher in the Eastern Jin Dynasty, and known as the Wang Youjun of the world. Because his works are variants of the ancient law, they are outstanding in nature, and he thinks that he has learned from the past and the present, and later generations respect him as a calligrapher, calling Preface to Lanting "the best running script in the world".
Wang Xizhi's Preface to Lanting, which is praised as "the best running script in the world", is an exquisite work of art; Wang Xizhi's real book has also reached the "unique"; His cursive script is also very distinctive, creating a precedent for a generation; His calligraphy "All Become Ancient Style" was a bold innovation at that time.