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How to Count the Knots of a Handmade Rug
Knot density, often measured in knots per square inch (KPSI) or knots per square decimeter (KPD), reflects the level of craftsmanship and detail in the weaving. While a higher knot count does not automatically mean a rug is superior in beauty or durability, it often indicates more intricate design possibilities and greater time invested by the weaver. Learning how to count knots is a valuable skill for anyone interested in evaluating or collecting handmade rugs.
Step 1: Understand What Knots Are
Handmade rugs are created by tying individual knots of wool, silk, or cotton onto the warp threads that run vertically through the loom. Each knot represents a tiny portion of the rug’s pattern. Depending on the weaving tradition, different knot types may be used—such as the Persian (Senneh or Asymmetrical) knot or the Turkish (Ghiordes or Symmetrical) knot. Regardless of type, each knot contributes to the overall density of the rug.
Step 2: Flip the Rug Over
To accurately count knots, it is best to turn the rug over and examine the back. The back of a handmade rug reveals the true knot structure more clearly than the front, where pile length may obscure the weave. On the reverse side, you can see the small square or diamond-like impressions of each knot tied into the foundation.
Step 4: Consider Variations
Because handmade rugs are crafted by human hands, knot counts may vary slightly across different sections of the same rug. To ensure accuracy, repeat your measurement in two or three areas and take an average. This is especially important in tribal or village rugs, where weaving irregularities are more common.
Step 5: Interpret the Results
Knot density alone does not determine a rug’s value, but it is a strong indicator of complexity. Tribal rugs may have lower counts, ranging from 30–80 KPSI, yet still be highly prized for their bold designs and cultural authenticity. City rugs, especially those from regions like Isfahan (Esfahan), Qom (Ghom), or Hereke, can reach 300–600 KPSI or higher, allowing for finely detailed patterns. The higher the density, the more time and skill required to produce the rug.
Final Thoughts
Learning how to count knots is an essential step in appreciating the artistry behind handmade rugs. By examining the back of the rug, measuring carefully, and understanding the meaning behind the numbers, collectors and enthusiasts can better evaluate craftsmanship and make informed decisions when purchasing or appraising. Ultimately, each knot represents not just a technical measurement, but also the dedication and cultural heritage of the weaver who tied it.
Step 3: Use a Measuring Tool
Next, place a ruler or measuring tape on the back of the rug. Most professionals use measurements in inches, but centimeters are equally valid. Position the ruler so it aligns with the rows of knots. Count the number of knots along one inch (or one centimeter) horizontally. Then, count the number of knots vertically in the same unit of length.
For example, you might count 10 knots horizontally per inch and 12 knots vertically per inch. Multiply these two numbers together to calculate the total knots per square inch:
10 × 12 = 120 KPSI.