Long before Chinese numerology meant avoiding the number four on a car license plate, it meant a specific nine-cell diagram: the Lo Shu, or river map, a three-by-three grid holding each of the numbers one through nine exactly once, arranged so that every row, every column and both diagonals sum to fifteen. Chinese tradition credits its discovery to a pattern seen on the shell of a divine turtle emerging from the Luo river, a legendary origin story that situates the diagram inside the same cosmological world as the Yijing's trigrams, with which the Lo Shu became closely associated in Han-dynasty and later correlative thought.
The Lo Shu is not primarily a fortune-telling device in its classical use; it is a structural diagram, deployed to correlate numbers with directions, seasons, and the eight trigrams of the Yijing in a single coherent cosmological map. Later Fengshui practice absorbed the grid directly into its own vocabulary as the Nine Palaces, jiugong, a compass-based scheme assigning each of the nine numbers to a direction and used to evaluate the numerical and directional qualities of a building or a plot of land, one of the more technical and least publicly visible layers of Fengshui practice.
This gives Chinese numerology two historically distinct roots that later popular usage tends to blend together: an old, structurally rigorous cosmological diagram, and a newer, much more loosely systematic body of number-based folk belief. Understanding the Lo Shu's original cosmological role, rather than reading it backward through the lens of modern lucky-number superstition, is necessary to see what actually connects Chinese numerology to the wider Yijing-based tradition it grew out of.