Following

The seventeenth hexagram, Sui ("Following"), places Dui (Lake) above Zhen (Thunder). Thunder sunk within the lake, movement resting in gladness, gives the image of things falling into willing sequence, one leading and others following. It follows Enthusiasm in the King Wen order.

Sui holds a further position in the xiantian, or Earlier Heaven, arrangement, the binary ordering devised by Shao Yong in the eleventh century and traditionally ascribed to Fu Xi: 26th of 64, apart from its seventeenth place in the King Wen sequence above. This was the Fu Xi ordering that the Jesuit Joachim Bouvet sent from Beijing in 1701 to Gottfried Wilhelm Leibniz, who recognized its broken and unbroken lines as his own binary 0 and 1.

Read from the bottom, the six lines of Following run yang, yin, yin, yang, yang, yin. A later interpretive layer absent from the original Zhou Yi, the nuclear hexagram (hu gua), treats lines two through four as a lower trigram and lines three through five as an upper one; here they combine as Xun over Gen, forming hexagram 53, Development (Jian), a hidden figure first associated with the Han-dynasty scholar Jing Fang, whose Yijing commentary of the first century BCE is credited with the earliest appearance of nuclear trigrams. Following's King Wen partner is hexagram 18, Work on the Decayed (Gu); most of the sixty-four pair this way, related by turning the whole figure upside down, while the eight hexagrams built from a single doubled trigram pair instead by inverting every line. Mawangdui (1973) orders hexagrams by trigram, not King Wen; names here follow Wilhelm and Baynes, 1950, not Legge, 1882.

The Judgment, in paraphrase, promises supreme success where perseverance is maintained and there is no blame, for one leads best by first knowing how to serve and adapt. The Image speaks of the superior person going indoors to rest at nightfall, following the natural order of activity and repose. The core theme is following and adapting, whether being led or leading through responsiveness. Moving lines transform into their opposites and generate a second hexagram that refines the reading.

The Judgment and Image paraphrased above draw on two of the Ten Wings, commentarial texts appended to the Yijing and traditionally credited to Confucius, though the attribution was already doubted within the Chinese tradition by the eleventh century and modern scholarship instead dates their composition to roughly the fourth to second century BCE, well after the Zhou Yi core itself. Wang Bi's third-century commentary read passages like this one from Sui philosophically, playing down the trigram image-correlations earlier commentators relied on, while Zhu Xi's twelfth-century Zhouyi Benyi pushed back the other way, insisting the book remain readable as the divination manual it began as. In the King Wen sequence, Following (Sui), hexagram 17, is paired with its inversion: Work on the Decayed (Gu), hexagram 18. Translations of the Judgment above vary by tradition: Richard Wilhelm's 1924 German rendering, carried into English by Cary Baynes for the 1950 Bollingen edition, gives the text a mystical, aphoristic cast, while James Legge's earlier and more literal 1882 translation for the Sacred Books of the East series reads the same lines closer to a historical record than a philosophical one.