Piano four hands (French: À quatre mains, German: Zu vier Händen, Vierhändig, Italian: a quattro mani) is a type of piano duet involving two players playing the same piano simultaneously.[1] A duet with the players playing separate instruments is generally referred to as a piano duo.[2]
Music written for piano four hands is usually printed so that left-hand pages contain only the part for the pianist sitting on the left, while right-hand pages contain only the part for the pianist sitting on the right. The upper part (right) is called primo while the lower part (left) is called secondo.