A Divination Manual with a Philosophy Grafted On

The I Ching or Yijing ("Book of Changes") is one of the oldest Chinese classics, built on sixty-four hexagrams, each a figure of six broken or unbroken lines, to each of which are attached a "judgement" and short line-texts read to interpret the flux of a situation in divination. Its oldest core, the Zhouyi, is a Western Zhou divination text of roughly the ninth to eighth century BCE, terse and oracular, reflecting the practice of casting yarrow stalks (earlier, of reading the cracks in heated turtle shells).

What turned this manual into a philosophical classic is a set of later appended commentaries, the "Ten Wings," traditionally but wrongly ascribed to Confucius and actually composed over the following centuries, which read cosmology and ethics into the hexagrams and gave the book its account of yin and yang, of change as the fundamental reality, and of the sage's attunement to it.