The screen on Si, south south east
Si runs from 142.5 to 157.5 degrees, centred on 150. It is the branch of the snake, the hour of nine to eleven in the morning, a fire mountain between Xun and Bing. Its opposite is Hai at 330, the seat of Tianhuang, so a grave sitting Hai faces Si, and whatever stands on Si is its facing hill.
The star ring places Tianping here. A screen stands between a seat and the draught: it hides, it shelters, and in the old phrase it covers a weak side. That is the imagery; it describes a job a hill does, not a fortune.
A screen keeps wind off; it does not hide a flaw
An ordinary star is a confirmation only, and what Tianping confirms is shelter. A hill on Si that is low, wide and even, closing the gap in front of a site, is doing a screen's work. For a site sitting Hai and facing Si, that hill is the table mountain; the school likes it about desk height seen from the stone, close enough to close the view, low enough not to press.
The third part of the name, covering a weak side, is the one people misuse. A screen covers only what it stands in front of; if the hill on Si is missing, the star does not stand in for it. In the school's phrase, the sky answers the ground; it is never a patch over it.
What this means on the ground
Tianping sits in the Si sector of the star ring. At a grave sitting Hai, stand behind the stone along its face, level the plate, three readings, and sight the facing hill. Between 142.5 and 157.5 it is the Si screen. Then judge it: is the ridge level, is it whole, is the height right, is there a gap in the middle for wind to run through.
For a house or shop, stand inside the door facing out. A low building, a line of trees or a bank on 150 degrees that breaks the wind from the front is the Si screen. A tall tower on Si is not a screen but a press, judged as such before any star is noted.
Common mistakes
Reading the name as protection. People see Screen, assume the site is sheltered, and never walk out to check whether a hill is there. The star describes a form; the form has to exist. Using the star to excuse an open front: a bare, windy facing on Si stays bare and windy.
Taking the bearing from a map, which cannot show the height of a hill from the stone, the one thing that matters for a screen, or reading Tianping on a phone app. Confusing a screen with a press: a hill too tall and too close on Si is not a sheltering form, and the star does not soften it.
Questions people ask
What is the Tianping star in feng shui?
Tianping, Heaven's Screen, is the Tianxing star paired with Si, the mountain at 150 degrees. An ordinary star, its name is a folding screen: shelter, wind kept off, covering. It confirms a low, even hill on that bearing.
What should the hill in front of a Hai grave look like?
A grave sitting Hai faces Si, so the hill on Si is its facing hill. The school wants it low and level, about desk height from the stone, whole, close enough to close the view without pressing. Tianping then agrees with it.
Can Tianping protect a house with nothing in front?
No. The star confirms a hill that is there and does not stand in for one that is missing. An open, windy front on Si stays open until you plant, build or screen it on the ground; then the reading changes.
If you are unsure whether the hill in front of your plot is a screen or a press, send photos and bearings for a reading, or learn to judge it on the Ganzhou field course.