In his book on the piano concertos, Cuthbert Girdlestone pointed out the similarity between the opening of this movement and that of Mozart's Symphony No.
1, K. 16, written when he was eight years old.
This juvenile work was composed for an orchestra of oboes, horns and strings.
A comparison illustrates how far Mozart had developed in the intervening 20 years:

Both works start with "a vigorous and rhythmical attack and a light answer, quiet and tuneful".
In the earlier work, the whole ensemble plays question and answer phrases and repeats them in their entirety:
The orchestration of the piano concerto is subtler and more differentiated.
In the early symphony, the answering phrase consisted of block harmonies, but in the concerto it opens out into flowing lines of counterpoint, initially featuring just two horns and a bassoon:
On repeating this, a different group of instruments plays the answering phrase, with "the unusual sound of the violins providing the bass for the solo clarinets":
Roger Kamien and Naphtali Wagner have analysed in detail Mozart's use of bridge themes in the exposition of the concerto's first movement.
Simon Keefe has analysed the character of the dialogue between the soloist and the orchestra in the concerto's first movement.
In his book on the piano concertos, Cuthbert Girdlestone pointed out the similarity between the opening of this movement and that of Mozart's Symphony No. 1, K. 16, written when he was eight years old. This juvenile work was composed for an orchestra of oboes, horns and strings. A comparison illustrates how far Mozart had developed in the intervening 20 years:

Both works start with "a vigorous and rhythmical attack and a light answer, quiet and tuneful". In the earlier work, the whole ensemble plays question and answer phrases and repeats them in their entirety:
The orchestration of the piano concerto is subtler and more differentiated. In the early symphony, the answering phrase consisted of block harmonies, but in the concerto it opens out into flowing lines of counterpoint, initially featuring just two horns and a bassoon:
On repeating this, a different group of instruments plays the answering phrase, with "the unusual sound of the violins providing the bass for the solo clarinets":
Roger Kamien and Naphtali Wagner have analysed in detail Mozart's use of bridge themes in the exposition of the concerto's first movement. Simon Keefe has analysed the character of the dialogue between the soloist and the orchestra in the concerto's first movement.
Piano Concerto No. 22 (Mozart)