What are oracle bones and how are they used?

Made from turtle shells or other animal bones, oracle bones helped ancient Chinese people make daily decisions. Oracle bones were used by fortune-tellers, most prominently during the Shang dynasty.

Fortune-tellers would keep many oracle bones in their shop. A client asks a question, and the fortune-teller writes representative symbols onto the oracle bone. Then they apply heat to it until it cracks. Depending on the way it cracks, a different fortune would be read.

Source: http://www.ancient.eu/Oracle_Bones/

Oracle bones are pieces of bone or turtle shell that were used in ancient China for divination purposes. They were primarily used during the Shang Dynasty, which lasted from around 1600 BCE to 1046 BCE. The bones were inscribed with questions or issues facing the ruler or community, and then heated until they cracked. The cracks were interpreted by diviners, or priests, to provide answers or insights into the questions posed. This practice was believed to allow communication with ancestors or spirits and provide guidance on important matters such as warfare, agriculture, and governance. Oracle bones are considered one of the earliest forms of Chinese writing, as the inscriptions on the bones represent some of the earliest examples of the Chinese script.