The King Wen sequence is the traditional order of the 64 hexagrams, the one that gives each its number from 1 to 64. When we talk about Water, that 29 comes from here.
The pairs
The order runs two by two: 1 with 2, 3 with 4, and so on up to 63 with 64. Each pair follows a fixed rule:
- In 28 pairs, the second hexagram is the first one turned upside down, its inverted hexagram. For example, Initial Obstacles and Immaturity.
- Eight hexagrams look the same upside down. Those are paired with their opposite hexagram: 1 and 2, 27 and 28, 29 and 30, 61 and 62.
Beyond the pairs, nobody has found a formula that explains the full order.
The two halves
The book is split in two: the upper canon, 1 to 30, which opens with "Activity" and "Passivity," and the lower canon, 31 to 64, which closes with "After the End" and "Transition." The book ends on something that isn't finished yet.
Origins
Tradition credits the order to King Wen, the founding figure of the Zhou dynasty. Scholars treat it as part of the received text, with no evidence of a single author. A silk manuscript from the second century BCE, found at Mawangdui, has a different order altogether. One of the Ten Wings, the Xugua, tries to explain why each hexagram follows the one before.
For more, read The King Wen Sequence.