Preparing for the Future: Late Shang Dynasty Tortoise Carapaces for Divination
In the later period of the Shang dynasty (as Shang people called: “Great Settlement Shang”), both the political economy and social culture made significant strides forward. When confronted with the unknown, however, the Shang people relied on divination to communicate with the supernatural and to foretell the future. Tortoise shells and ox scapulae, regarded with spiritual nature, were transformed into oracles through a series of steps including being cut, polished, and drilled or chiseled before they were heated and cracked to answer the charge posed for divination. This exhibition presents material aspects on the preparation of carapaces to highlight their forms and variations.
Common Divination Materials of the Late Shang
The most commonly used divination materials in the late Shang were tortoise shells and ox scapulae. Concerning the former, the plastron was typically used as it is the flatter part of the shell and thus more easily drilled or chiseled.
The steps in preparing ox scapulae for use in divination included paring the scapular spine on the reverse side, sawing away a part of the glenoid cavity (socket) to create a half-moon-shaped section or platform, sawing away the tuberosity (rounded prominence) at the edge of the socket to create a right-angled corner, and polishing the surface.
The tortoise plastron used for divination was sawn apart from the carapace near the bridge, with the bridge remaining attached to the left and right sides of the plastron. Colloid and scales were pared, and the surface was rubbed and polished to create a smooth surface. The bridge was also often grinded to form obtuse or right angles.
Preparation of Tortoise Carapaces
Through contrasting tortoise carapaces used for divination practices with the shape of original carapace, it can be categorized into three types basing on their appearance and form: “unsawed” (complete carapace), “fanned” (carapace is sawed into two halves), and “reshaped” (carapace undergoes sawing and paring).
“Unsawed Tortoise Carapaces” The majority of extant tortoise carapaces used in divination have been sawed, whereas those unsawed are rather rare, suggesting that the latter were seldom suitable to use in divination.
“Fanned Tortoise Carapaces” The most common method to prepare a tortoise carapace for divination was sawing it into two halves along the scapular spine, with any protrusions on the edge of the carapace occasionally being sawed away and pared. According to records contained in oracle inscriptions, in tributes carapaces were paid in “pairs”, each comprising two “fanned”. This also indicates that live tortoises were not offered as tribute objects. A left or right of fanned tortoise carapace can be judged by the shape of the shell or the direction of the divination inscription.
“Reshaped Tortoise Carapaces” Reshaped tortoise carapaces refer to those that were sawed and pared into an oval shape as well as having holes bored. Their shapes resemble that of a sole of a shoe, and the carapaces are thus also referred to as “shoe-sole-shaped tortoise carapaces.” Among extant oracle bones, reshaped carapaces are rare. However, in pit YH127 in Yinxu excavated by the IHP, fourteen have been discovered thanks to research and restoration, making pit YH127 one of the few to contain relatively large number of reshaped tortoise carapaces.
Regarding the bored round holes on all discovered reshaped tortoise carapaces, there are two prevailing theories: (1) To produce volumes: a cord would be threaded through the holes of several carapaces to create a volume; (2) storage: after the hole was drilled, the carapaces would be stored for later use. Moreover, considering that the grooves and other markings avoid the round holes, it be ascertained that the holes were drilled before the carapaces were chiseled.
Practice Inscriptions on Tortoise Carapaces
The majority of oracle bone inscriptions are divination records, but few are records of current events or even inscription practice. The specialists responsible for carving oracles must have repeatedly practiced until they could create neat strokes on oracle bones. In extremely few cases practice inscriptions are evidently scraped off before proceeded to make divination.