Rug knots

(a) The Turkish knot has a band of wool, and its two woollen ends sticking out (Ј) The Persian knot does not at first appear to have a knot until you look sideways on and see the wool wrapped around the warp.
And, finally, the Spanish knot: note that the knot is tied to alternate warp threads and easy identification is possible. Let us now summarize and put Key No. 2 into action.
Key No. 2

If it has a Turkish knot is it made west of the Dividing Line
but including the Caucasus, Tabriz (Persia) and a few
Kurdish tribes.
If it has a (Sehna) Persian knot it is made east of the line.
If it has a Spanish knot it is made in Spain.

Therefore, if you look at a rug and you are not certain whether it is Persian or Turkish, you have only to took at its knot and you can now be more definite. There are only a few towns in Persia which use the Turkish knot, and if you study their types, designs and dyes, applying the other keys, your identification will be correct.