The dragon branch, and the axis it shares with Xu
Chen and its opposite Xu are both earth branches, so the line from 120 to 300 degrees is an earth axis. On our luopan it is also the axis of the Dipper: Chen carries the handle star and Xu the head star.
As a water mouth, Chen has its own place in the sanhe water method, where the four earth branches are the storehouses and a mouth on a storehouse is well regarded. Our school reads the mouth with the eyes first: is it narrow, is it held by hills on both banks, does the water pass out of sight before it leaves the valley?
Heaven's Bar, the Dipper's handle
The star on Chen is Tiangang, Heaven's Bar, the handle of the Northern Dipper: authority, hardness, severity. It is a common star. In Lai Buyi's method the star is a seal pressed on a judgement already made, and on Chen the seal has a hard edge.
A peak on Chen that is sharp, dark and leaning over the site is read as the severity in the name, and the master looks for what softens it, a lower hill in front or water between. A peak on Chen that is square-topped and sits back is read as the authority in the name, a solid guard.
What this means on the ground
House: inside the door, back to it, reading out. Grave: behind the stone, along its face. Three readings, luopan level, no steel within arm's reach. Chen runs from 112.5 to 127.5.
Its north line is also the line between Zhen and Xun, so a reading of 113 or 114 puts the stone on two trigrams and two elements at once, and the trade turns it a couple of degrees toward 120. A reading near 126 leans on Xun, the same trigram, a milder lean. To measure a peak or a water mouth, stand at the site, not at the foot of the hill, and sight across the dial.
Common mistakes
Taking a phone's true north reading as the luopan's. Measuring from a map, which gives true bearings and no slope. Setting a stone on 113 because the book says Chen, with the trigram line one degree away.
Reading the dragon animal into the mountain, as if a Chen seat had anything to do with being born in a dragon year; the branch on the dial and the branch in a birth chart share a name, nothing more. And the oldest error: finding a square peak on Chen, calling it Heaven's Bar, and never checking whether a dragon comes in behind the site. A guard with nothing behind it guards nothing.
Questions people ask
What direction is Chen on a feng shui compass?
Chen is east-southeast, 112.5 to 127.5 degrees on the luopan with 120 at the centre, between Yi and Xun. It is an earth branch, the dragon, the hours of 7 to 9.
What does sitting Chen facing Xu mean?
The back of the stone or house is on 120 degrees and the front looks to 300, west-northwest. Both ends are earth branches; on the Tianxing luopan both carry Dipper stars, the handle on Chen and the head on Xu.
Is a water mouth on Chen good?
The sanhe water books treat Chen as a storehouse direction for an outgoing mouth. That is a formula, not a sighting. A master first checks that the mouth is narrow and held by hills, then reads the bearing.
To learn to read a peak and a water mouth with your own eyes, join Master Zhang's field course in Ganzhou.