Tierpspolskan is an iconic polska from the town of Tierp in Uppland.
It is a Bondpolska, a characteristic dance form from the iron foundry district where the nyckelharpa traditionally is most played.
It is played on both fiddle and nyckelharpa, but it is considered to be a nyckelharpa tune, and most players in Uppland know it.
Here is a YouTube recording with Viksta-Lasse, a legendary fiddler, playing it in his old age. And here is a great old-time dance band playing it as a hambo.
To the left is a photo of the old housing for iron workers at a foundry in Tierp.
To the left is a video of me playing Tierpspolskan on the fiddle.