Introduction to Cao Cao's handwriting: The word "Gun Xue" is engraved on the southeast of Cao Gong Pavilion, which is the only handwriting of Cao Cao still alive. According to historical records, in the third year of the reign of Emperor Xian of the Han Dynasty (April 192 AD), Cao Cao defeated the Yellow Turban Army at Yangshan and Gepo (now Geshan), killed He Yi, captured the Yellow Shao, and collected Xu Chu to wash away the dust and enjoy the scenery. , visited the great scenery of Yangshan Mountain. Cao Cao was completely attracted by this magical creation of nature, and he couldn't help but feel relaxed and happy and full of pride. The talented Cao Cao asked for the four treasures of his study and wrote the two characters "Gun Xue" with great speed. The word "gun" lacks three points of water because at that time, except for the solitary mountain Yangshan, this area was surrounded by swamps, so the water was right in front of us.