An earth branch that opens the Kun trigram
Wei is one of the four earth branches, Chen, Xu, Chou and Wei, that the old books call storehouses. On the dial it is where fire gives way to earth: Ding at 195 is the last fire, Wei at 210 the first earth, and the line between them at 202.5 is a trigram border as well.
First in Kun, Wei is the gentler end of the group. Kun in the centre is the heavy earth; Shen beyond it already turns to metal. Wei is earth still warm from the fire beside it; the goat and the afternoon hour fit it.
Wei as incoming dragon, as water, as sitting, and the star that keeps
A dragon entering from Wei comes in from the south-south-west, and the master wants a slow, broad, settled ridge there, not a sharp one. Water from Wei should arrive at the front and turn, not slide straight past. Sitting on Wei and facing Chou puts the back to the south-south-west and the door to the north-north-east.
The star on Wei is Tianheng, Heaven's Constant, an ordinary star named for holding on and lasting. Master Zhang reads it the plain way: a thick, even Wei dragon or a broad, unbroken Wei backing is the ground the constant star describes. A flat, lifeless slope on 210 gets no help from the name.
What this means on the ground
Measure as always: inside the door, back to it, or behind the stone along its face, three readings, middle value, no steel. Then walk. For a Wei dragon, go up the slope behind the site on 210 and feel whether it is one continuous body or a string of lumps.
Inside the mountain, 202.5 to about 207 is close to Ding and still carries fire; 213 to 217.5 is close to Kun's heavier earth; 207 to 213 is clean Wei. In 2027 Tai Sui sits on Wei, so digging, building or setting a stone on this side that year needs the dates chosen with care; not forbidden, but timed.
Common mistakes
The first is a phone on true north, which overseas can push a Wei reading into Ding or Kun. The second is confusing Wei with Kun because both are earth and south-west: Kun is the corner trigram at 225, Wei the branch at 210, with different stars. The third is sitting a stone on 202.5, the fire and earth line, or on 217.5 against Kun.
The fourth is reading the 2027 Tai Sui as a reason to abandon a good Wei site; the year changes when you work, not whether the ground is good. The fifth is copying a lucky south-west from a book without checking what lies on 210.
Questions people ask
What direction is Wei on a feng shui compass?
South-south-west, 210 degrees magnetic, from 202.5 to 217.5. Wei is the goat among the twelve branches, earth by element, the first mountain of the Kun trigram, between Ding and Kun. Its opposite is Chou at 30 degrees.
Is it bad to build on the Wei side in 2027?
Not bad in itself. 2027 is a Ding Wei year and Tai Sui sits in Wei, so the custom is not to break ground or set a stone on that side without a proper date. The land is judged as always; only the timing changes.
What does Heaven's Constant mean on Wei?
Tianheng is the star on Wei, named for keeping and lasting. It is an ordinary star. The Tianxing school uses it to confirm a broad, settled Wei dragon or backing already seen on the ground, never to make a poor slope good.
If your plot or family grave has its back to the south-south-west, book a site reading and Master Zhang will walk the Wei slope with you and tell you what it is doing.