Hand-knotted rugs are constructed by tying individual knots around pairs of warp threads. The two dominant knot types are the asymmetric knot and the symmetric knot — and the choice of knot has significant implications for both the look and the durability of the finished rug.
Asymmetric knot (also called the Persian knot or Senneh knot) wraps the yarn fully around one warp thread and only partially around the second. This allows the weaver to produce finer detail, more pronounced curves, and intricate floral patterns. It is the standard knot used in most Persian city-workshop rugs (Tabriz, Kashan, Isfahan, Qum, Nain), as well as in fine Indian, Chinese, and Egyptian production.
Symmetric knot (also called the Turkish knot or Ghiordes knot) wraps the yarn evenly around both warp threads. The resulting knot is mechanically stronger but produces a slightly less refined appearance. It is the dominant knot in Anatolian (Turkish), Caucasian, and Kurdish rugs, as well as in many tribal Persian weavings.
Knot count (knots per square inch, or KPSI) is one of several factors used to evaluate a rug's quality. A typical village rug might have 80–150 KPSI; a fine Persian city rug 300–500 KPSI; an exceptional Qum silk rug can exceed 1,000 KPSI. Knot count alone, however, is not a complete measure of quality — wool grade, dye quality, and design execution matter equally.