What is the role of a pivot chord in a modulation?

A pivot chord plays a crucial role in modulation by linking two different keys smoothly. It serves as a common chord that is functional in both the original key and the target key, allowing for a seamless transition between the two tonalities. This connection helps to create a sense of continuity in the music, making the shift to the new key feel natural instead of abrupt.

When composers use a pivot chord, they often choose one that is shared by both the tonic of the original key and the tonic of the new key. This strategy effectively prepares the listener for the change and ensures that the modulation feels cohesive. While establishing a new key signature or changing time signatures can be important aspects of a piece, these functions are not directly related to the concept of a pivot chord in modulation. Similarly, providing rhythmic stability is not the primary purpose of a pivot chord, which is specifically focused on harmonic connections between keys.