The Lo Shu square is another important and most ancient symbol widely used in feng shui analysis. It is also called a magic square as its nine chambered 3×3 grid square features a unique arrangement of numbers from one to nine. It is unique because the sum of three numbers in any direction fo the square, horizontally, diagonally, or vertically, is 15. 15 is the number of days taken by the new moon to reach full moon.
The three-sided-grid pattern corresponds to the eight sides of the Bagua symbol, and is associated with its eight trigrams. Lo Shu unlocks the time dimension for feng shui, and allows practicioners to decide exactly when is the best time to make changes in the site, home, or interior decoration.
Chinese tradition says that the first image of the Lo Shu square was seen by Sage Yu. He saw this mystical arrangement of numbers as white spots which were arranged in this particular pattern on the nine-grid shell off a tortoise which emerged from the rive Lo in 2205 BC. The ancient Indian system of astrology and yantra technique has created yantra squares. These planetary squares were used to generate signs that control the spirit of planets. The square of Saturn or “Shani” has the exact same arrangement of numbers as the Lo Shu square.
As dots on a tortoise are awkward to use, for practical use the Lo Shu square is used as a 9 chambered 3×3 grid with numbers in each chamber.