Markings in the bones and shells that were produced by heating them. This practice was known as divination. Oracles, people who were considered to have a special wisdom and the ability to foretell the future, would read the cracks in the bones and answer questions asked of them by government officials. Those questions might be about almost anything, because it is believed that the Shang kings were highly superstitious. But they probably asked questions about the worship of ancestors, what military actions should be taken, and whether those actions would be successful.
In addition to the bones and tortoise shells, official accounts are also derived from writings on bamboo and wood. The existence of these written records shows that writing was already highly developed by the Shang period. Its origin in China is still unknown.4