During the Spring and Autumn Period and the Warring States Period, letters were written on bamboo slips. In order to prevent others from peeking, they were covered with wooden boards and tied with ropes. The rope was called "绯". We now say " "Keep silent" means to seal it well. Later, the envelope was sealed with clay and stamped on the clay, indicating that the letter had not been opened. The words on the clay seal are the seals studied by philologists today. Clay writing.
Letters have many names, such as letters, handwritten letters, calligraphy slips, ruler slips, ruler Han, etc. Letters written by celebrities before the Tang Dynasty were called calligraphy by later generations, which is a calligraphy that attaches great importance to it. The Palace Museum's treasure "Pingfu Tie", which was exhibited to celebrate the 80th anniversary of the museum, is a letter written by Lu Ji of the Western Jin Dynasty to greet a sick friend. This 9-line cursive script with 84 characters is the earliest surviving authentic calligraphy and celebrity manuscript in China. ~