This classic comes from the Supplement to the History of Tang Dynasty by Li Zhao in the Tang Dynasty: "Huai Su, a monk in Changsha, is good at cursive writing, and he says that he is a sage of grass. Abandon pens and pile them up, and bury them at the foot of the mountain, nicknamed' Pen Tomb'. "
Huai Su, a monk in the Tang Dynasty, was born in Changsha and was a disciple of Xuanzang. He is famous for his wild grass and inherits Zhang Xu's brushwork, and is known as "crazy element."
Huai Su loves cursive script and practices hard, claiming to have got the calligraphy secrets of the cursive saint Zhang Xu. He piled up his discarded pens and buried them at the foot of the mountain, which is called a "pen grave".