What does "una corda" indicate in piano performance?

"Una corda" is an instruction used in piano performance that translates to "one string" in Italian. This term signifies that the pianist should use the soft pedal (or una corda pedal) on the piano, which alters the sound produced by the instrument. Specifically, when the soft pedal is engaged, it shifts the entire action of the piano over so that the hammer strikes only one of the two or three strings associated with each note. This results in a softer and more muted tone.

The context of the soft pedal is essential to understanding "una corda." It is used to create a delicate and subtle sound, ideal for passages that require a gentle touch. This expression allows the pianist to convey nuanced emotions in their performance, highlighting the expressive possibilities of the instrument. Thus, "una corda" emphasizes the importance of dynamics and tone color in piano music.