Of these four groups the Persian has the largest number of classes, some of which can only with difficulty be distinguished from one another. They may, however, conveniently be divided into the following sub-groups, depending on the technical peculiarities of the weaving and the material of the warp, so that the task of learning the class of a particular rug will be greatly facilitated by first determining to which of these sub-groups it belongs, and then eliminating the others from consideration.
| Cotton Warp |
| One thread of warp to each knot doubled under and hidden at back. |
| Sehna Knot (A) |
| Kashan Kermanshah Khorassan Kirman Meshed Mir Sarabend Sarouk. |
| Ghiordes Knot (B) |
| Gorevan Herat Herez Serapi Tabriz | ||||
| Each thread of warp equally prominentat back or one slightly depressed. |
| Sehna Knot (C) |
| Feraghan Mahal Muskabad Royal Sarabend | ||
| Ghiordes Knot (D) |
| Gulistan Iran Joshaghan Luristan Sultanabad | ||||
| quincunx effect of weft at back. |
| Sehna Knot (E) | Sehna | |||
| Ghiordes Knot (F) |
| Hamadan Ispahan (modern) |
It should be remembered, when studying the foregoing table, that all classes of rugs are subject to occasional variations in the technicalities of their weave, as for instance, the Herats may have woollen warp and Sehna knots; the Tabriz very often have linen warp; some of the Feraghans, Mahals, Muskabads, and Sehnas have the Ghiordes knot and some of the Sultanabads have the Sehna knot; the Joshaghans may have woollen warp; and in modern Ispahans the weft sometimes crosses twice between two rows of knots.
| Woolen Warp, Ghiordes Knot. |
| One thread of warp to each knot doubled under at back | (G) |
| Bijar. Niris[37] | |
| Each of the two threads of warp to a knot equally prominent at back, or one slightly depressed | (H) |
| Karadagh. Suj-Bulak. Kurdistan. Afshar. Mosul. Shiraz.[38] | |||
| Quincunx effect of weft at back | (I) | Karaje.[39] | ||||
With reference to size, these rugs may conveniently be divided as follows:
| Rugs invariably of carpet size |
| Gorevan. Mahal. Muskabad. Serapi. Sultanabad | ||
| Rugs frequently, but not always, of carpet size |
| Bijar. Herat. Kermanshah. Khorassan. Meshed. Sarabend. Tabriz. | ||
| Rugs frequently seen as runners |
| Hamadan. Karaje. Kurdistan. Mosul. | ||
Of the sub-groups represented on Page 284, “A” includes those that have the closest and finest woven texture. In this respect the Kashans, Sarouks, and Kirmans are, in the order named, superior to the others; and the Kermanshahs are the coarsest and the least evenly woven. In sub-group “B” the Tabriz are the best woven and have the shortest nap. The Gorevans and Serapis have several concentric medallions, in which are designs of archaically drawn leaves, and have generally the so-called turtle border. The Herats have the typical Herati border. Of the classes of sub-group “C,” the Royal Sarabends are the closest woven. The Feraghans are slightly coarser and the Mahals and Muskabads are much coarser and have longer nap. The Luristans, Joshaghans, and Gulistans are the best woven of sub-group “D.” At the back of Luristans each half knot is distinct from the other like a separate bead; and in a few Joshaghans each half knot is almost as distinct. Both Irans and Sultanabads are coarsely woven. Comparing sub-groups “E” and “F,” the weave of Sehnas presents a file-like appearance at the back; and in Hamadans the weft is of much coarser diameter than in the other two classes. The Bijars of sub-group “G” are much stouter than the Niris and have one of the two threads of weft to each knot more completely doubled under the other. The webs at the ends of the Niris are very much longer than those of Bijars. Sub-group “H” contains the Kurdistans, Suj-Bulaks and Mosuls, all of which are woven in territory where for generations the Kurds have held sway, and show Kurdish characteristics. The Western Kurdistans may easily be distinguished by their brown colours, nomadic character, and coarse warp and weft. The Persian Kurdistans are very stoutly and firmly woven, and usually have one of the two threads of warp encircled by a knot depressed below the other. The Mosuls have each of the two threads of warp encircled by a knot equally prominent at the back; and a characteristic feature is the coloured, crudely spun yarn of weft, which on account of the size of its diameter stands up as high as the yarn of the knots at the back. In a typical Suj-Bulak the alignment of knots at the back appears uneven or serrated. The Karadaghs have Caucasian characteristics; the Afshars have coarse, wiry wool for the weft, and threads of warp strung so that each half knot is distinct.
Although the technicalities of weaving are the most reliable evidence for determining the class to which a rug belongs, the patterns are important guides. It will be well, therefore, to remember that:
A Persian rug is probably a Shiraz, Karadagh, Karaje, Mosul, Kurdistan, or Afshar, if the pattern is partly geometric.