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