The origins of astronomy can be found in the I Ching. Using the principle of astronomy, calendrical studies, and the I Ching to understand thoroughly the meaning of the unity of heaven and man is difficult. Nevertheless, we should study the I Ching little by little and fuse it with the principles of astronomy and calendrical studies. Then we can investigate the similarities in all things.
Nishikawa Joken, as quoted in The I Ching in Tokugawa Thought and Culture (2000) by Wai-Ming Ng, p. 139
Its name, "The Book of Changes," is suggestive; and we find throughout its contents the vague idea of change replaced by the more definite one of "transformation," the key-word of alchemy ... "The diagrams," [Confucius] says again, "comprehend the profoundest secrets of the universe; and the power of exciting the various motions of the universe depends on their explanation; — the power to effect transmutation depends on the understanding of the diagrams of changes." Here, in a word, is the ... general object of Chinese students of alchemy.