The classic Chinese divination text, also known as the 易经 yì​jīng, which interprets sixty-four hexagrams as a manual for understanding change and philosophy.

An influential Taoist book from the Eastern Han dynasty, traditionally attributed to 魏伯阳 wèi​bó​yáng, which uses the symbolism of the 周易 zhōu​yì to explain internal alchemy; often called the "Ancestor of all Alchemy Books"