Question submitted by Alice, Age 10

Q: What is the left pedal and why use it?

A: The left pedal can help pianists create beautifully expressive sound, and you are encouraged to try it out on your piano at home. The official name of the left pedal is the una corda; if you speak Italian, you know that means “one string.”

Take a look inside the piano at the strings. You will notice that each piano key is attached to a hammer that strikes the strings. All treble (high) hammers strike three strings, whereas those in the lowest bass have one to two strings. When the una corda is down, the hammer strikes only one string—the reason for this pedal’s name.

The una corda on a grand piano actually shifts the keys slightly to the right. The whole keyboard actually MOVES! Try it on the next grand piano you see. What happens inside the piano is that the hammers move too, then striking only one string. If you have an upright piano at home, you will notice that the una corda might not work like this. On some uprights, the una corda moves the hammer closer to the strings (and the keys might depress a bit).

Now to the magical result: the una corda changes the tone quality, making the sound darker, muted, and less vibrant. Pianists describe this as a “color” change. While the sound can also be softer, it is not really a “soft pedal” because you can still play quite loudly. This color change is perfect for sections marked leggiero (light), sec (dry), or pianissimo (very soft). On an upright piano, the left pedal may help you play with easier control of dynamics.