Kalevi Aho claims the Twelfth (2002‑03) as his largest symphony (the BIS recording of No 8, however, is almost two minutes longer) but it undoubtedly requires the most performers of any of his 14 to date. It was designed to be played on the slopes of Mt Luosto in Finnish Lapland and the booklet back cover shows a photograph of the premiere, with the main orchestra in a valley, the audience dotted between the trees and the chamber orchestra halfway up the mountain. Unseen are the brass, percussion and vocal soloists dotted additionally around this natural, open-air concert space which BIS has recreated with remarkable effectiveness for this compellingly realised recording inside Lahti’s Sibelius Hall.

The Luosto Symphony falls into four large movements, each with descriptive titles suggestive of Lappish culture. “The Shamans” opens with exhilarating drum tattoos and fanfares that reminded me of Panufnik, while the ensuing orchestral textures have something of the Sinfonia Antartica about them, not in the depiction of extreme cold but rather of the space of the Finnish tundra. “Winter Darkness and Midsummer” encapsulates the region’s single most defining feature (to outsiders): the extremes of utter dark and constant light that oscillate through the seasons.

In “Song in the Fells”, soprano and tenor in vocalise with solo saxophone add a delicate yet dark-hued picture of the landscape. In the final “Storm in the Fells”, the shaman drums return as the work texturally as well as musically ties up its threads. Like Vaughan Williams’s Seventh, Aho’s Twelfth is a work of immediate effect yet needs time to make its full impact. Part of that impact is a new annual festival that aims to revisit the work with different performers every few years. Only in Finland.