Knot Count and Rags — Weaving Density Told Through Feel, Not Numbers

When browsing the bazaars of Qom, you often hear rug merchants ask, "How many Raj is this?" The answers come back as "70," "80," or sometimes "90" or "100." While this way of speaking is not very familiar in Japan, in the local context, it's the fundamental unit for discussing quality.

The quality of Persian rugs is expressed by "knot count" and "Raj." Both describe the same density using different terms, but if you're not familiar with them, the numbers alone can be difficult to interpret. Here, instead of just presenting the raw numbers, I'd like to discuss density by translating it into a tactile experience that can be felt with your fingertips and seen with your eyes.

What is a Knot? — A Unit for Counting Ties

A "knot" refers to a tie. Persian rugs are made by hand-tying colorful pile threads, one by one, to the warp threads stretched on a loom. The total number of these ties per a fixed area is the knot count.

Tying serves two purposes. First, the pile threads are firmly secured to the warp, causing the surface pile to stand upright. This contributes to the rug's resilience when stepped on. Second, since each knot is independent, if one part is damaged, it is less likely to affect the surrounding area. This is the foundation of the durability that allows rugs to be used for decades.

"Knots per square meter" refers to how many knots are tied per square meter, while "knots per square centimeter" refers to how many are in a one-centimeter square. In Japan, square meter notation is common in retail stores, while locally, as I'll explain next, they use "Raj."

Raj — The Persian Unit for Counting Warp Threads in a 7cm Width

"Raj" is a traditional Persian unit of density, counting how many warp threads are arranged in a 7cm width. For example, 70 Raj means there are 70 warp threads in a 7cm width, which is approximately 10 threads per 1cm width. Since each warp thread has a knot, this roughly corresponds to the number of knots per 1cm width.

For Qom silk rugs, 70-80 Raj indicates a high-quality standard. This translates to about 10-11 knots per centimeter, or 1 million to 1.2 million knots per square meter. The thickness of the thread and weaving tradition support this density.

Rugs exceeding 90 Raj are woven by only a handful of workshops, such as those from the Jamshidi lineage. At this level, the unevenness of the knots is barely perceptible to the touch, and the surface appears as smooth as a single piece of fabric. Works with 100 Raj or more are referred to as "the pinnacle" even locally.

The Feel of 1 Million Knots per Square Meter

The term "1 million knots" might be too large a number to grasp easily. Imagine placing a 1cm ruler on the rug and seeing 10 knots lined up between the markings. That means one knot per millimeter.

Even a skilled weaver can advance only about 5,000 knots per day at most. If we consider a living room-sized rug of 2m x 3m, it would total 6 million knots. Theoretically, it would take one weaver over 3 years to complete.

The work from the Jamshidi workshop in the video, dyed with natural dyes, took 18 months to weave. Watching it, you can get a more concrete sense of the time and labor involved in creating a piece considered among the world's highest density.

Over 100 Raj May Indicate Machine Weaving

Here are some cautionary notes for buyers. Rugs "exceeding" 14 knots per cm (= 98 Raj) are extremely rare when hand-woven. It's safer to assume that descriptions like "2.25 million knots" or "2.89 million knots" seen in the market are likely for machine-woven rugs.

Machine-woven rugs do not "tie" in the same way; instead, the pile is implanted using a different method. They are characterized by the absence of the distinct knot patterns unique to hand-weaving on the back, and the rows are mechanically uniform.

Be wary of listings on auction sites, etc., that emphasize "100% silk, high density" but have an excessively high knot count. If these conditions are combined with the seller being an individual with unknown details, and no photos of the back or with a ruler on the product page, the likelihood of it being machine-woven increases further.

At Golestan, we publish photos of the knot count with a ruler for all our products. We do this to help customers verify for themselves how many knots are aligned per centimeter, which also helps prevent such deception.

The Craftsman's Hand Revealed on the Back

Just as important as the density number is the appearance of the back. How uniformly are the knots aligned? Are they tightly packed without gaps? Are the rows straight and orderly? If you imagine each knot as a millimeter-sized brick, it's easier to visualize the difference between a neatly stacked wall and a crooked one.

A truly good rug has a back that is as beautiful as its pattern, smooth to the touch, and densely woven. The honest workmanship of the weaver, which isn't always visible from the flamboyant front, is revealed on the back.

Focus on Feel, Not Just Numbers

Knot count and Raj are clear entry points when choosing a rug. However, solely chasing high numbers can sometimes obscure the crucial aspects of color, composition, and depth of dyeing.

Many 70 Raj rugs surpass others in dyeing and composition. Whether it's 1 million or 1.4 million knots, I believe choosing a rug where you feel "this color, this composition" is the one you will cherish for a long time.

At Golestan, we include density photos with a ruler and photos of the back on our product pages. If you find a piece you're interested in, I encourage you to look at the back's appearance along with the numbers.