Introduction to rock coffin: Rock coffin is one of the burial styles of ancient ethnic minorities in southern China. It is a type of cliff burial and is mainly popular among nobles. Drill several holes in the cliff and nail wooden stakes, and place the coffin on top; or place one end of the coffin in the cliff hole and put the other end on the wooden stakes nailed on the cliff. Due to thousands of years of wind and rain erosion, the coffin is as light as charcoal, weighing no more than fifty kilograms. The bottom and cover of the coffin are made of a single piece of wood. The craftsmanship is quite rough and the marks of knives and axes are clearly visible. There are two square holes in the bottom, cover and two walls. Inside the coffin are the bones of the ancestors and some funerary objects.