Two years ago the Northern Streams strain of Edinburgh's Ceilidh Culture season was cursing Iceland and the volcanic ash that threatened to disrupt its programme.

This year, the festival's opening concert was celebrating a country whose folk traditions haven't made a huge impact this side of the North Sea alongside Norway and Sweden, whose folklore has become rather more familiar.

There were familiar aspects in the presentations of all three duos involved, with Scotland's traveller-tradition bearers Lizzie Higgins and Sheila Stewart cited as song sources by Icelandic-English pairing Bara Grimsdottir and Chris Foster, and Swedish twosome Karin Ericsson Back and Maria Misgeld, and hardanger fiddler Lajla Buer Storli illustrating the mouth music that followed the burning of instruments in Norway in an eerie echo of the Gaels' experience.

All three groups had their merits, although Grimsdottir and Foster's set, featuring recreated ancient Icelandic instruments as well as guitar and kantele (or Finnish harp) accompaniments, became wearying and worthy and wasn't enhanced by the accompanying slide show.

Back and Misgeld's harmonising, diddling, lullabies and outraged reading of Ewan MacColl's traveller anthem, The Moving-On Song, coalesced in a sparkling a cappella performance, their voices dovetailing beautifully and showing a great understanding built up over a decade together. Storli and fellow Norwegian, ballad singer Kim Andre Rysstad, took a more spontaneous approach that sometimes felt offhand but at its best showcased her ability to match his relaxed singing with deft fiddling and tightly phrased vocal expression.