Before an Ubosot is constructed, nine pits are dug in the ground; one under where the Buddha will be placed and eight where the sema stones will mark the cardinal directions. A ball shaped stone called a Luk Nimit is buried in each pit and the sema is placed on top. If the Ubosot has been rebuilt or is a royal temple there will be a double or triple sema stone in each of the directions. The Ubosot is where the ceremonies and rituals for the monks take place and is, therefore, the holiest part of the temple. You will notice that the entrance to the Ubosot will almost always face the east. Occasionally the ubosot is contained within a low wall called a Kamphaeng Kaew (crystal wall).