The most basic of looms has been used to produce exquisite Oriental rugs. For the wandering nomads, two trees growing a few feet apart can become a loom when a couple of poles are stretched between the trees.

Looms can be horizontal or vertical. Vertical looms are further divided into the village loom, the Tabriz loom and the loom with rollers. The village loom is the simplest with an upper and lower beam, both horizontal, fastened firmly to two vertical posts. The warp threads are rolled around the lower beam and their free ends are brought together in bundles that are fixed to the upper beam.

Whether horizontal or vertical, the loom has a simple mechanism that allows the weaver to divide the warp threads into two sets so that the warp threads can be reversed after each shoot of the weft. The artisan first weaves a selvage. Several shoots of weft are made to obtain a narrow band which is intended as a firm edge for the knotted areas.

The knots of yarn are the basis of the carpet's pile. The most common types of knots are the Turkish (Ghiordes) knot and the Persian (Senneh) knot. An important factor in determining a carpet's origin is the identification of the type of knot with which the carpet is tied.

Flat Weave

The basis of a carpet are two sets of threads -- the fixed warp threads which run from north to south, and the weft threads which are woven from east to west and separate each row of knots. The Turkish knot is knotted around two warp threads while the Persian knot is knotted around one warp thread and looped under the next in an TS' pattern.

Each knot is tied by hand. Skillful artisans can tie about 15 knots a minute or about 8,000 a day. This means it would take the artisan more than two months to weave a carpet that is 10 feet by 6 feet and has a hundred knots per square inch. Typically, a rug of this size would be woven by several artisans working together from a chart which shows the number of knots to be tied in each color.

Weft-wrapping or Soumak

In addition to knotted rugs, the Caucasus is known for producing Soumaks. These are pile-less carpets made with a flat weave technique of wrapped weft threads -- a technique used throughout the Middle East. The geometric decorative elements used for the Caucasian soumaks are based the designs used for knotted carpets. A typical layout includes superimposed medallions in the form of notched stars. Typically made of wool, these Soumak carpets are strong and compact.

The majority of Oriental rugs, including those from Turkey and the Caucasus, use Turkish knots. Many Turkoman and Persian rugs use Persian knots, but Turkish knots also are common in those regions. The geographical dividing line seems to be the Caspian Sea. To the west of it, the Turkish knot is used almost exclusively. To the east, the Persian knot dominates. Lying on both sides of the dividing line, Persia uses both types of knots.