What does inverted bucket mean?

Dǒ o dǒ u refers to robbing a tomb. It has many names, such as "touching gold as the captain" and "moving mountains". The history of this profession can be traced back to the slave society in China. At that time, there was a custom of burying things in tombs, and grave robbers came into being. No matter monarchs, nobles or ordinary people, they will put what they liked before their death in the graves of the dead.