The short answer
Qi Men Dun Jia, 'the Mysterious Gates', is the strategist's art — historically used for war, statecraft and timing. It arranges stems, stars, doors and deities across a nine-palace board for a given moment, revealing the hidden structure of a situation.
The heart of it
The board layers several systems at once: the Nine Stars, the Eight Doors (Open, Rest, Life, Injury, Delusion, Fear, Death, Scenery), the Eight Deities, and the Three Wonders. Reading their interaction for your question and direction is the heart of the method.
Why it is worth your attention
Use it for consequential, time-sensitive decisions — a negotiation, a launch, an important journey. Choosing a favourable hour and direction from the Qi Men board is a classical edge on high-stakes moves.
Try it yourself: Qi Men Dun Jia is free on FengMaster, computed to the letter.