Mozart: Piano Sonata in B-Flat, K.333, I

Here we have our introduction to Sonata form. Sonata form seems to be the most open of all the forms. In this Sonata Mozart takes many liberties with the form. We begin immediately into our Group 1 theme. This group takes the form of a rounded binary form. Our first phrase lasts 10 measures and ends on a PAC. It seems to start over, but in fact we quickly modulate into the dominant key for our B section of Group 1. The ends on a HC in our original key and we come back to the original material. This recapitulation ends on a cadential extension, then a PAC. We now transition and move again to the Dominant key, but with the inclusion of new material we move into our Group 2. This theme is much shorter and moves quickly to closing material. This whole section is repeated again (group 1, group 2 and closing) as is normal for the form. Our Developmental section takes the them from group 1 and runs with it, through a range of keys, starting with the relative minor, eventually bringing back our transitional material and ending on a big HC in the original key. When our Group 1 returns, we start in the sub-dominant key in order to make the transition return our group 2 into the original B-flat key. We come back to B-flat and onto our closing material, which we extend out once again to a final PAC. Hooray!