This is a Norwegian development of the violin and has four playing strings and 4 or 5 sympathetic strings which help to give it its extraordinary ringing sound. There are numerous different tunings of the fiddle but it is generally at least a tone up from the normal violin tuning.
Double stopping is a feature of the playing, and the music ripples and mesmerises with trills reminiscent of a bubbling stream.
It was banned from churches for a while because of its association with the devil (according to the church authorities) Indeed sometimes players would enter a state of trance during a dance.
The earliest Hardanger Fiddle still in existence dates from the 1750s. I bought my Hardanger Fiddle from Hauk Buen of the famous Buen family of fiddlers and makers, although my fiddle was made by Knut Flattin about 70 years ago.
This piece is called Halling aus dem Hallingtal.