In some Thangkas, another piece of fabric appears on the lower section of the mounting.
It is of different color and is called "the door or the root of the thangka" [Tib: tang-sgo].
It is a symbol of the cosmic ocean and plays an important role during meditation session. Under the influence of China brocades with dragons or water motives are used for this special part of mounting.
The photo shows the same thangka in three different versions:
1. No root - 2. Large root window - 3. Small root window