This is what I see
It's the shadow of the trunk on the wall. I've removed it, and now I see that what I saw is not a part of the trunk that is stripped, but actually that shadow.
Still, it seems pretty risky. I've understood junipers have a linear sap flow - the root under a branch feeds that branch - so cutting through it interrupts the sap flow to that branch and may kill it.
The shari I have made on my juniper all are under branches I removed or jinned. As the parts of the trunk that feed other branches get thicker, it 's a bit easier to see where the live veins are.
[edit]Noticed I have to correct something:
A root under a branch feeds the branch above it: that's not completely true. What I mean is that that root has a path to a branch - not necessarily straight up to that branch[/edit]