Listen to Sonata in B-Flat Major, K. 358/186c: I. Allegro online. Sonata in B-Flat Major, K. 358/186c: I. Allegro is an Instrumental language song and is sung by Viktoria Postnikova and Gennady Rozhdestvensky. Sonata in B-Flat Major, K. 358/186c: I. Allegro, from the album Viktoria Postnikova & Gennady Rozhdestvensky. Piano Ensembles, was released in the year 2019. The duration of the song is 5:27. Download Instrumental songs online from JioSaavn.