 Conversely, in the Mozartian concept, the piano entry is always a moment of great importance, and he varies it considerably from concerto to concerto.The only exception to this rule is the dramatic intervention of the piano in the second bar of the "Jeunehomme" Concerto, which is, however, minor enough not to disturb the overall structure.Rather than the Prelude being a "preliminary canter" (Hutchings) of the themes of the concerto, its role is to introduce and familiarise us with the material that will be used in the ritornello sections, so that we get a sense of return at each of these.