What is the function of a cadenza in a concerto?

The function of a cadenza in a concerto is primarily to showcase the virtuosity of the soloist. A cadenza is an elaborative solo passage typically placed before the final section of a movement, allowing the performer to demonstrate technical skill, creative expression, and interpretative ability. It often features intricate passages, rapid runs, and dramatic flourishes that highlight the soloist's talents, making it a moment of clear personal expression within the structured framework of the concerto.

While other aspects of the cadenza may include elements of transition or thematic variation, its main purpose remains to put the spotlight on the soloist, giving them an opportunity to shine and enthrall the audience. This moment usually breaks away from the orchestral accompaniment, hence emphasizing the solo performance, further contributing to its role in demonstrating virtuosity.