Bartók wrote these duos for a German compendium of graded violin repertory. Most use original folk themes, of half a dozen national types. The duos are not intended as an hour-long performance set. Some of the later Duos do, however, cohere well together, to form 5-6 minute performing brackets of pieces. Individual pieces are useful as encores at two-violin or even quartet concerts. Bartók liked the idea of a graded collection so much that it pushed him toward his larger Mikrokosmos series for young pianists. He imaginatively reworked half a dozen of the duos for piano as Petite Suite.
Note by Malcolm Gillies