After the bodies and sacrifices are put in place, they should be nailed on the coffin cover, which is called "town nail" by the people. Town nails generally use seven nails, commonly known as "children's nails", which is said to make future generations prosper.

It means that the deceased will no longer be disturbed, so that they can smoothly enter the underground world. So the bottom of the coffin is very thin, which is what people think can facilitate the dead to enter hell and reincarnate smoothly. )

Prevent fraudulent corpse. (Actually, it is because people may have convulsions after death, which was easily misunderstood in ancient times. )