It’s seven years since Shetland fiddler Chris Stout and Dundee-born harper Catriona McKay released their previous duo album, White Nights. In between times came the superb Seavaigers with the Scottish Ensemble and there’s a palpable connection with both of these releases here in that the pair continue to refine and explore their approach to the folk tradition while operating at a level of musicality that puts them easily in the chamber music and classical soloist orbits.

Bare Knuckle denotes the gloves coming off and it’s an apt title not just for the track of that name but for the album as a whole. This is a duo exposing flesh and feelings in a series of conversations that can go right out to the edge of musical expression, sometimes ecstatically, as in the extraordinary, dizzying, adrenaline-fuelled Moscow Rush, sometimes atmospherically, as witness the keening, majestic impressionism of Tingaholm.

Stout’s tonal range and bow mastery – now gliding on Villa-Lobos’ Bachianas Brasileiras No 4 Preludio, now choppy as the North Sea in winter – and McKay’s sense of enquiry and harmonic strumming and shape-forming are as breathtaking as they are excitingly, gorgeously, emotionally satisfying. A landmark release.