Reworking of his own Sonata for 2 pianos and percussion (1937).
Having moved to the United States due to World War II, Bartók added a full symphony orchestra to the score in 1940. This was done to expand the concert repertoire of the duo Bartók and his wife, pianist Ditta Pástory.
1. Assai lento - Allegro
2. Lento, ma non troppo
3. Allegro non troppo

