oracle bone

Oracle bones are pieces of ox scapula and turtle plastron which were used in pyromancy – a form of divination – during the Late Shang period (c. 1250 – c. 1050 BCE) in ancient China. Scapulimancy is the specific term if ox scapulae were used for the divination, plastromancy if turtle plastrons were used. A recent count estimated that there were about 13,000 bones with a total of a little over 130,000 inscriptions in collections in China and some fourteen other countries.

Diviners would submit questions to deities regarding weather, crop planting, the fortunes of members of the royal family, military endeavors, and similar topics. These questions were carved onto the bone or shell in oracle bone script using a sharp tool. Intense heat was then applied with a metal rod until the bone or shell cracked due to thermal expansion. The diviner would then interpret the pattern of cracks and write the prognostication upon the piece as well. Pyromancy with bones continued in China into the Zhou dynasty, but the questions and prognostications were increasingly written with brushes and cinnabar ink, which degraded over time.