The Yijing has two layers. The older is a Western Zhou divination manual: sixty-four hexagrams of six broken or unbroken lines each, with terse and often cryptic judgments and line statements, consulted by manipulating yarrow stalks or, later, tossing coins. The younger is the Ten Wings, a set of commentaries appended by the Han and traditionally though not credibly attributed to Confucius, which reinterpret the whole as a systematic account of change, correlating the hexagrams with cosmic process, moral development and social order. That second layer is what made it a philosophical classic rather than a fortune-telling book, and it became shared property across the Chinese intellectual world — Taoists, Confucians and later Buddhists all worked with it, and Zhu Xi wrote extensively on it. Analects 7.17 has Confucius saying that with fifty more years to study the Yi he might be free of major faults, and tradition holds he wore out the leather binding cords of his copy three times.