1 The couple were buried in a double coffin tomb, but one of the bodies was not well preserved and the empty coffin had completely rotted. This kind of situation is quite common, and it has happened in Shanxi, Henan, Shaanxi and tombs of past dynasties.
The same tomb was buried together, but one party was not buried together for various reasons. This kind of situation is mostly double coffins and bed sheets coffins, but it happened in the tombs of late Chu nobles in Nanyang, Henan Province.
3. The relocation of the tomb belongs to the second burial. This situation was found in some tombs in the south of the Yangtze River from the Northern Song Dynasty to the Southern Song Dynasty, that is, there were bones in the coffin, but for other reasons, the coffin was empty, presumably related to family or family struggle.
As for the coffin, it is related to two materials. 1 says there is a kind of heavy wood in the South China Sea. Using this kind of wood as a coffin can keep the body from rotting for thousands of years.
There is a so-called shady place in geomantic omen, which is not suitable as a cemetery. Folk superstitions believe that burying a corpse (sudden death) in this place will turn the corpse into a zombie and harm people. This place is called a burial ground.
Online novelists borrow these materials and use their personal imagination to create the concept of corpse coffin.