If a giant played a tune on the cable stays of the Second Severn Crossing bridge, with its double span of fanned-out suspension wires, it would sound like a basso-profondo version of the kora. This West African instrument, formed of a halved calabash covered in cowskin, equipped with a long neck, a notched double bridge and 22 strings made out of fishing gut, is classed as a double-bridge harp-lute. Such a dry description does little to evoke the silvery, rippling, liquid sounds the kora produces in the hands of a real master, and Seckou Keita, descendent of Mali royalty on his father’s side, and Senegalese professional musicians or griots on his mother’s, is one of the finest of these today. Matching him in virtuosity is Catrin Finch, whose own brushes with royalty include a stint as the Prince of Wales’ harpist, and whose teacher (and now mother-in-law) the harpist Elinor Bennett is married to the former leader of Plaid Cymru, the Welsh nationalist party, putting her firmly into the crachach (upper-crust) category of Wales’ movers and shakers.

Two koras, one with one neck and one with two (an original idea of Keita’s) and two harps, one an electro-acoustic concert harp and the other a small electric folk harp, stood on the platform under a swirl of stage smoke and a harp-string pattern of lights evoking sunbeams filtering through a slatted roof. All very atmospheric, a bit hippy-dippy and perhaps designed to appeal to any middle-aged members of the audience who might have bought their first kora recordings in the 1970s and listened to them in something of a daze. Once Finch and Keita had taken their seats at their respective instruments, the concert commenced briskly with the first of a number of pieces whose titles combined Welsh (a language in which Finch is fluent) with Mandinka, Keita’s mother tongue. “Genedigaeth koring-bato” means “Birth of the kora” and begins with a repetitive figure on the kora, to which the harp responds with a recognisably Western melody. Both Wales and Senegal have traditions of bardic music in which a descant is sung or played over an initial tune, but the styles of development – particularly from the rhythmical point of view – are quite different. This became clear once the kora took the principal voice, and the hypnotic cross-rhythms, based on a pattern of three-against-two and four-against-three, started to accelerate, embellished with glittering descending scales and tiny repeated cells of melodic patterns. Eat your heart out, Reich and Glass! In an interview in the accompanying (highly informative) booklet by Andy Morgan, Finding the One, Finch admits that she finds the Senegalese rhythmical patterns challenging to lock into, and this was clear from the performances throughout the evening. It reminded me of the duets between Stéphane Grappelli and Yehudi Menuhin, where the jazz fiddler ran rings round the classical violin virtuoso.

“Bamba”, the second piece, was dedicated to a Sufi elder prominent in Senegalese Muslim culture. “Robert Ap Huw meets Nialing Sonko” saw Catrin Finch moving onto the smaller folk harp to play tunes transcribed from the difficult tablature manuscript left by the medieval Welsh harpist Robert Ap Huw, accompanied by a countermelody from the kora tradition. “Les bras de mer” brought out all the rippling liquidity of both kora and harp, evoking the coastlines of Wales and Senegal – a common theme of several pieces in this concert. During a brief spoken interlude (complete with puff for the duo’s CD, Clychau Dibon, named for the Welsh word for bells alongside the Mandinka name for hornbills that pair for life – but spend the night in separate trees) we heard about the history of both harp and kora, and got a flavour of the bantering humour that clearly makes this partnership a pleasurable one for both parties. “Future strings”, a duelling piece that definitely left the harp in second place, ended the first half of the programme.

The second half began with a cheerfully galloping piece called “Ceffylau” (Horses), but then the music took on a darker tone. “Combo celtaidd”, meaning “Misty Celtic” had an authentic feel of Celtic twilight. “Tryweryn” was a dirge lamenting the flooding of the Welsh village of Capel Celyn in 1965 to provide water for Liverpool, a particularly sore point with Welsh nationalists then and now. “Llongau Terrou Bi” or “Ships of Terrou Bi” refers to what is now a pleasure resort in Dakar, Senegal, but was once near the slavers’ island of Gorée, through whose ‘door of no return’ slaves were shipped across the Atlantic on a one-way passage. The concert concluded with a sweet, reflective duet, “Mossoulou”, wonderful late-night music to conclude a late-evening concert.