What is a flat-weave?
In the most basic terms a flat-woven rug is created with the use of a loom to interlace two sets of threads, the lengthwise warps and widthwise wefts, thus producing a flat surface with no pile.
"The interlacing of strands to create a textile evolved from the simplest finger-plaiting to the fixing of warps on a loom making possible the efficient and rapid construction of tightly woven cloth... The oldest illustration of a loom is on the side of an Egyptian bowl of c.4000 BC, but most probably the loom developed with the earliest civilizations." - Kilim: the Complete Guide by Alistair Hull and Jose Luczyc-Wyhowska
"The possibilities open to the weaver for free expression in flat weaving are limited, however, by the techniques of weaving; this is in contrast to the more versatile work of the knotted carpet makers. As the pattern on a knotted pile carpet is made up of colored wool tied round the hidden warp threads, and forms no part of the structure, each knot may be a different color. In this way free-flowing compositions taking any form can be drawn. Not so with flat weaving, for the disciplines of integrating color changes into the structure limit the variety and dimension of the patterns that can be drawn. The weaving technique used, therefore, has a direct and conclusive influence on the patterning of the rug." - Kilim: the Complete Guide by Alistair Hull and Jose Luczyc-Wyhowska
Slit-weave: utilizes a weft-faced plain weave but incorporates blocks of color leaving a vertical slit between the boundaries of the two colors. This technique results in patterns that are geometric and diagonal to maintain the structure of the rug. "All flat weaving people use slit-weave extensively as the basis for floor rugs, covers, and bags." Kilim: the Complete Guide by Alistair Hull and Jose Luczyc-Wyhowska
Dovetailing weave: similar to the slit-weave technique ,except the wefts at the edge of each block of color share the same warp, eliminating the slit between color borders. The dovetailing of the two colors leaves more of a blurred division of colors.
Weft-faced Patterning: a technique that produces patterned color change in a way that is fundamentally different from slit-weave and dovetailing. "In weft-faced patterning, colored wefts are woven so that they only show on the front face of the weave when they are needed...When the weft is not being used on the face of the weave it floats freely on the back of the rug." ( Kilim: the Complete Guide by Alistair Hull and Jose Luczyc-Wyhowska) This technique results in a rug which either has a face and back that have a reverse image, or a back with long floats of yarns that make the rug non-reversible.
Weft wrapping: also known by the eponym Soumak weave (though not accurate), with this technique the weft is wrapped around the warp in any number of complex mathematical combinations which allow for interesting textures and directions in the weave.
These are only a few of the most commonly used flat-weave techniques, there are a multitude of other techniques that have not been included here.
What's in a name?
Kilim versus Dhurrie versus Soumak:
There are many names for flat woven rugs, most often the name they are given relates to where they are woven. Kilim is the name given to most all flat-woven rugs made in Persia - the actual weaving technique used can vary. Dhurrie is the name given to most all flat-woven rugs made in India - again the weaving technique can vary. Soumak, the name derived from the Caucasian town of Shemakha (also known as Soumak) as noted perviously is incorrectly assigned to flat-woven rugs made with the weft wrapping technique, and it assumes that this technique was only employed in Shemakha itself. When in actuality this technique has been used for centuries in locations all over, including Peru, Egypt, and Persia. Soumak is now more commonly used do describe the technique used to weave the rug.
"The essential aim of any flat-weaver is to create patterning with wool threads that are exposed on the face of the rug by alternating and varying the colors of the threads, whilst at the same time maintaining both structure and rigidity."
- Kilim: the Complete Guide by Alistair Hull and Jose Luczyc-Wyhowska