The dotar (literally meaning ``two strings''), is the instrument par excellence of the bakhshi. It comes from a family of long-necked lutes and can be found throughout Central Asia, the Middle East and as far as the North East of China in Xinjiang. Its ancestor is probably the "tanbur of Khorasan" as depicted by Al Farabi (10th century) in his essay Kitab~Al-Musiqi Al-Kabir. Maraqi (15th century) in his Jame~Ol Alhan also describes two types of two-string tanbur: one which he calls the tanbur of Shirvan (a region in the south east of the Caucasus) and another which is the Turkish tanbur.
In Iran, the dotar is played mainly in the north and the east of Khorasan as well as among the Turkmen of Gorgan and Gonabad. The instrument remains the same but its dimensions and the number of its ligatures vary slightly from region to region. Two types of wood are used in the fabrication of the dotar. The pear-shaped body is carved out of a single block of mulberry wood. Its neck is made of either the wood of the apricot or the walnut tree.
It has two steel strings, which in the past were made of silk or animal entrails. Thus, Haj Ghorban Soleimani's dotar used to have silk strings which he replaced in the 60s with strings of steel because they are more resistant.
The dotar is tuned in fourth or fifth intervals. The frets, made in the past from animal guts, have been replaced by nylon or steel which have the advantage of being more resilient and less expensive. They are placed in chromatic progression.
The technique for playing the dotar consists of plucking the strings without a plectrum, following a descending and an ascending movement which involves the index and often several other fingers. The music is ornamented by the rapid repetition of notes (tremolo). Often, in order to fortify the fingers, they are soaked in henna. ``When the harvest season comes'', says Haj Ghorban Soleimani, "we get up at dawn and cut the wheat by hand from morning till night. It hardens the skin on the fingers. That's when you should hear me play."