The zither is a folk instrument descended from the medieval psaltery. The zither typically consists of a flat wooden soundbox, over which is stretched two sets of strings. The first set is a set of four or five melody strings. These melody strings are stretched over a fretted fingerboard and sit closest to the player. They are played with the left hand, plucked by either the fingers or a plectrum. The other set of strings are accompaniment strings. These a plucked with the fingers of either hand. The concert zither can have up to thirty seven accompaniment strings.
There are several types of zither, including the concert zither (described above), the alpine zither, which features an extra set of contrabass strings which are usually arranged at an angle to the melody and accompaniment strings, and the fretless zither which has no fingerboard and all strings are played in an open position, similar to a harp.
The zither gained great popularity in England after World War II when it was featured in the soundtrack of Carol Reed’s classic noir film The Third Man.