The sky's marketplace: Tianshi and the Tianshi enclosure
Chinese sky maps divide the stars near the pole into three enclosures. The Tianshi enclosure is the market, ringed by stars named for trading states. The school keeps the name to its own words: exchange, wealth that gathers, people coming and going. Gen is a corner trigram mountain, the north east, where in the old lore things finish and start again. A market on that corner is the image.
On the land it asks for a hill with people's warmth in it: rounded, approachable, with roads or valleys leading to it, not a lonely crag.
Carrying the best of the sky: a noble star on a six elegant mountain
Only four of the 24 stars are noble, and Tianshi is one. When the incoming range enters on Gen, the school says the dragon has brought the best of the sky with it; Gen being six elegant as well, the peak and water on this bearing are weighed with the same favour. A clean, upright peak on Gen is the finest attendant hill; water from Gen is welcomed as market water, busy and gathering.
Still, the sky answers the ground. The Cuiguan Pian names Gen among the noble bearings in its chapters on dragon, cave, sand and water, but the dragon must first be alive and the cave must hold. A dead range on Gen carries a noble star over nothing.
What this means on the ground
On the Tianxing ring of the school's luopan, Tianshi sits under Gen at the north east corner, between Tianchu and Tianbang. At a grave, read from behind the stone along its face; at a house or shop, from inside the door outward, three times, with no steel on the plate.
Sight every hill and the water mouth and note any that fall between 37.5° and 52.5°. A full, rounded peak there is marked as Tianshi. In a city the same bearing from the door is read for what stands on it: a busy market street, a kept corner building or a square where people gather suits the name; a dark alley or a vacant lot does not.
Common mistakes
The commonest mistake is to let the word market write the story: a noble star does not mean money comes. The second is to prefer the star to the ground, taking a scarred Gen slope because the ring says noble. The sky confirms, it does not rescue.
The third is measurement. A phone on true north can push a peak at 50° over the line onto Yin, or pull one at 35° up from Chou; only the luopan's magnetic needle on the site settles it. The fourth is reading from a map at home; the noble corner has to be sighted from the seat.
Questions people ask
What is Tianshi in feng shui?
Tianshi, the Heavenly Market, is the Tianxing star on Gen mountain, 45° north east. It is one of the four noble stars, and Gen is also six elegant. Its name comes from the Tianshi enclosure, the market of the Chinese sky.
Is a north east facing house lucky because of Tianshi?
The star is read on the hills and water around a site more than on the door, and only after the landform. A sound house with a well shaped hill or building on 37.5° to 52.5° gains a noble confirmation; a bad site facing north east gains nothing.
How is Tianshi different from Tianchu next to it?
Tianchu sits on Chou, 22.5° to 37.5°, an ordinary star of provision. Tianshi sits on Gen, 37.5° to 52.5°, and is noble. A peak at 40° is on Tianshi; at 36° it is on Tianchu. The degree decides, not the hope.
If your plot has a hill or a range on the north east corner, book a site reading with Master Zhang or join the field course in Ganzhou to have it sighted properly.