This piece is a ceramic container in the form of a coffin with lid, used to hold the ashes of the deceased. The roughness of the construction, decoration and glazing suggests that it contained the ashes of a humble person.

Cremation was not a native Chinese tradition, but was introduced to China with the coming of Buddhism after the 4th century AD. This new practice was first adopted by Buddhist monks in monasteries and then gradually extended to lay believers, particularly during the Song period (960-1279). Confucian officials, however, openly rejected cremation, considering the destruction of the body as an evil act against the Confucian, and traditionally Chinese, value of filial piety.

The front side of the coffin is incised with the image of a door surrounded by the names of the 'guardian spirits of the Four Directions': the Green Dragon of the East, the Red Bird of the South, the White Tiger of the West and the Dark Warrior of the North, who were meant to protect the deceased in the grave. The inscription also contains a date in Chinese lunar dating system. When associated with the reign name of an emperor the date is unambiguous, but when it is used alone, as in this case, it gives a range of alternative dates. For this object the style and manufacturing techniques suggest three possible dates: 1206, 1266 or 1326 AD.