The short answer
Flying Star Feng Shui (Xuan Kong Fei Xing) is a time-and-space system. It assigns nine stars to the nine sectors of a building based on its facing direction and the 20-year period in which it was built, then flies them forward each year and month.
The heart of it
Each palace of the home carries three numbers: the mountain star (people, health, relationships), the water star (wealth, opportunity), and the base star of the period. Auspicious combinations invite specific fortunes; troublesome ones — the 2, 5 and their pairings — invite illness or loss.
Why it is worth your attention
The annual stars change each Lunar New Year. Knowing where this year's 5 Yellow and 2 Black land tells you which corners to keep quiet and which to activate — a yearly tune-up rather than a one-time fix.
Try it yourself: Flying Stars (Xuan Kong) is free on FengMaster, computed to the letter.