Teacher's Day is said to have been written by Suo Jing, and it was handed down in ink. Song Xuanhe hid in the palace and was discovered in Xuanhe, Pu Shu. The original is unknown, but there are photocopies of ink circulating. The block-printed edition selected in this book once belonged to Wen Peng of Ming Dynasty, followed by an inscription of Wen Peng 15. Although there are different opinions on the authenticity of this post in past dynasties, its quaint book style undoubtedly reflects the charm of Jin people. The calligraphy pen of the whole post has a side, a flat pen tip, a heavy and dignified pen, a sharp edge, and often twists and turns in a little painting. It can be said that the calligraphy of this post is full of subtle changes in weather and brushwork, and this change is very subtle, which does not give people the suspicion of sharp edges and looks simple and elegant. It is precisely because of this weather that Wen Peng praised it as "the first ancient prose" in his postscript.