Väsen Biography (Wikipedia)
Väsen is a Swedish folk music band from Uppsala originally consisting of Olov Johansson (nyckelharpa), Mikael Marin (viola) and Roger Tallroth (guitar). Later André Ferrari (percussion) also joined the group. As of 2017 they have released 18 albums, featured on others, and have toured every year also outside of Europe. Since 2002, however, performances outside Sweden have tended to not include André Ferrari, owing to his reluctance to tour internationally and the economic advantage of a trio. Since then, Väsen has released seven albums (Trio, Keyed Up, Live in Japan, Väsen Street, Mindset, Live på Gamla Bion, & Brewed) in this “strings-only” format.
The band played on Nordman's debut album in 1994. On the Finnish group JPP's album String Tease, they were guest artists on two of the tracks.
They also regularly play with the American musicians Mike Marshall (mandolin) and Darol Anger (violin).