String instrument in East Indian folk music is considered as the principal music producing instrument. Supporting music of folk-tunes was hardly familiar in the rural areas in the past; talents were not also available for such acts. In spite of these drawbacks, some indigenous types of Tata Yantra - string instruments were devised in some particular areas within the last few hundred years. It appears that the sense of tune in the rural man induced him to devise both bowing instrument and plucking stroke-instrument in analogy with sophisticated instruments he came in contact with. And these instruments spread gradually along with the spread of popular music.
Dotara (literally, a two stringed instrument, i.e., the miniature, rustic sarod) is in use in Northern part of the Indian state of West Bengal, Bangladesh, lower Assam and Tripura. The actual source cannot be guessed, since it involves several factors: fixation of plate or plain wood underneath the two/three strings (finger-board), the skin surface at the bottom, use of bridge, and metal-string. Muga threads were also utilized in the past. Earlier animal guts served the purpose of strings.
Sarinda, the other string instrument which is played by bow, and is familiar in East Bengal (Bangladesh) where it is used in Bhatiali songs, was described by 19th century western musicologists in their works. It is made of a short single wood with hollowed belly covered partially by a skin over which three strings run up and down over a bridge at the bottom. Strings are tightened to the top-keys running over an extended thin plate. The instrument suggests somehow a miniature rustic imitation of violin-cum-sarangi. Sarinda is played by a bow being placed in an inverted position hung over breast and belly. The middle portion of the sarinda is also observed to be curved a little on two sides. While playing it is rubbed up and down by fingers on finger board and bowed at the curved portion just above the bridge.
Ektara, the handy drone-instrument of various shapes and sizes, is popular all over India under different names. In the eastern region the instrument contains variations. The popularly known ektara, which looks like a veena type is made of gourd-rind of coconut-shell fitted at the bottom of a bamboo or wooden tube over which a string runs. The string is tied to a peg at the top and placed on a bridge at the bottom. The bottom is covered by a string or a wooden plate.
Another tata yantra which is no less than an avanaddha instrument is named as khamak by Bauls of Birbhum (In West Bengal). A string runs inside a cylinder at the bottom to which a skin is fitted. The upper side of the string is tied to a peg which is held and pulled by hand. The string, plucked and struck on one end, is often tightened and released to produce varied resonance of rhythm. The instrument is also called gubgub in some areas. It is comparable with dudhuki of Orissa.
