This is one of the instruments included under the category of ‘open harps.’ These are divided in turn into ‘bow’ and ‘angled’ harps. The çeng belongs to the second category. In open harps the strings are stretched between the peg box and the resonator. There is nothing in front of the longest (and deepest) string. In closed harps, there is a third part that joins the two sides of the resonator and the peg box which form an angle. As in modern harps, this part is found in front of and parallel to the longest string.
The pegs and resonator are made from the same piece of wood in bow harps, which are the most primitive form and whixh the strings are stretched between those two. The earliest known examples, from the Anatolian, Mesopotamian and Egyptian civilisations, date back to around 1,000 B.C. Angled harps began to be used in the same areas but at a later date. These have an angle of some 70 degrees between the flat or curved resonator and the pegs. Some pictures of harps reveal a degree of up to 90 degrees.
Angled harps were used for thousands of years by Anatolian, Mesopotamian and Egyptian civilisations, and the latest to emerge was the Ottoman çeng. It was used up until the last quarter of the 17th century, but due to the difficulties in playing, carrying and tuning it, and the increasing popularity of such instruments as the tambur and santur, it slowly disappeared from the stage of history.