Candidate of science Dadar-ool-Syuryun is convinced that round, clay discs, which can be found in ornament of tile of Por-Bazhin is thought to be nothing but schematic depiction of a lunisolar calendar left by Turkic peoples, who are the ancestors of Tuvinian people.

They used this scheme to make a calendar with a cycle of five years like we have today.

In ancient ornament can be seen three circles. Inside the first one there are seven spots equidistant from each other and the centre. Inside the middle circle there are eight alternate circles and eight alternate triangles. Finally, inside the outer one there are twenty eight spots in symmetrical order which correspond to twenty-eight solar days and nights. According to the calendar one month consisted of 29 days or 30 days. All this was taken into consideration by ancient people.

Speaking about the place of building the fortress, it’s necessary to say that it is built just in the middle of the lake. Why? The main feature of the lake is its smooth surface that can reflect the moon, the sun and stars and even their trajectory. So, it is supposed that Por-Bazhin was the largest observatory of nomad peoples, built with the aim to study the sky.