In the beginning, the I Ching was primarily a book of oracles. The ancients of many civilisations depended on oracles for advice in their everyday lives as did their rulers in major undertakings.

Early oracles were designed to answer questions phrased for a yes/no response, the I Ching being no exception. 'Yes' was indicated by an unbroken line and 'no' by a broken line. As the need for a more enlightening advisor evolved, so did the I Ching, until someone consulting the oracle could interpret not only what his situation was at any given time, but also what might be the proper course of action.

There are two major systems in Chinese prediction: symbolic and numerical. In early hunter-gatherer cultures, animal bones and the markings on tortoise shells were associated with the symbolic. As people became more agricultural, bones and shells were replaced with plants, and numerical calculations involving yarrow stalks became the standard method for divining the will of the gods.

Confucius writes in the Ta Chuan that "The Changes have no consciousness, no action; they are quiescent and do not move. But if they are stimulated, they penetrate all situations under heaven."

The various instruments of divination are this stimulus for the determination of the proper hexagram containing the answer to the question being asked.