According to Xunzi Book of Rites, the complex funeral system of two coffins and five coffins originated in the Zhou Dynasty. This funeral system is quite complicated. In the Zhou dynasty, only the emperor could use it, but later, with the development of economy, some princes and ministers began to use this funeral system. The so-called coffin refers to the coffin containing someone's body, and the so-called coffin refers to the coffin outside the coffin. This kind of funeral is not only complicated, but also expensive, so in ancient times, ordinary people's families could not afford this kind of funeral system, and only princes and generals continued to use it.

When the emperor of the Zhou Dynasty was buried, he usually needed two coffins and five coffins, which means there were five coffins and two coffins. Of these five coffins, only one is the main coffin. Of course, it must be the emperor. The other four coffins are either buried with concubines or filled with a lot of gold, silver, jewelry and other sacrifices. At the periphery of these things, there is usually a small sarcophagus at first to protect the integrity of the subject. On the outermost periphery of these coffins and martyrs, there will be a thick layer of stone coffin to protect the whole tomb from being discovered.

In many movies of tomb raiding series, we can all see that after finding the tomb door, tomb raiders often use explosives to blast it to create a tomb door, which is usually made of stone. If it is a general tomb, you can often see the position of the main coffin after opening this stone gate, but in many cases, it is not so smooth.

In the middle of the stone gate leading to the sarcophagus, there will always be various hidden weapons, which is a protection mechanism that ancient people came up with to avoid grave robbers. Shi Guo is a heavy and big stone slab, which is used to protect the whole coffin. This slate has also become the outermost wall. If the outermost stone falls off, it is equivalent to exposing the whole tomb. The last layer of sarcophagus protects the real tomb owner, and the general sacrificial objects are all around. Such a huge project can't be built by ordinary people, so it can only be used by princes and princes in the end.