Since the Western Zhou Dynasty, it has been believed that jade can prevent corpses from rotting. After the death of the nobles, they began to cover their faces with jade. Since the Spring and Autumn Period and the Warring States Period, a small piece of jade called Han Yu has been put in the mouth of the deceased. This custom was particularly popular in the Han Dynasty. Jade toad is generally a jade cicada, which symbolizes the desire of people to lie dormant underground after death and emerge from the ground one day, and get a new life after cicada slough. Later, jade letters were made of jade, jadeite and jewels. It is said that after Empress Dowager Cixi was buried, there was a luminous pearl in her mouth. The treasure of Dongling was broken, its face was lifelike, it was dug up by grave robbers, and the body quickly began to corrupt. (Photo: Han Yu in Han Dynasty-Yuchan)