The Combination of Harmony and Counterpoint (cont.)
Diminution (Part III)
In the example below, one note (occasionally two) has been chosen from each linear unit and marked with a stem. The notes picked out below are those of the theme being varied - the variation decorates the melody of Twinkle, Twinkle Little Star.
A piece of music does not have to be a variation on a theme to follow the same principle - the decoration of a series of notes that are more structurally important.
There are no hard and fast rules for working out which notes are structural except that they must be at the beginning of end of the diminution and MUST be consonant with the harmonic unit (I, IV etc) being prolonged (see How to do a Schenkerian Analysis for more on this).
You may think that all Schenker is doing is giving obvious features complicated names. You do not need Schenkerian analysis to tell you, for example that there is a rising fifth in the second half of the first bar.
Schenker suggests, however, that connecting C and G in this way, the composer binds these two notes, and all those in between into a musical unit.
His revelation is that if you strip away this first layer of diminutions you find that you are left with a new layer of diminutions hidden below the surface of the music.
A good illustration of this is the last five bars of the example above - from the G in bar 4 to the C bar 8 the notes picked out by upwards stems describe a descending fifth progression. This is made clearer in the next example (click on the example or here).
One of the criticisms of Schenkerian analysis is that it ignores rhythm. The above analysis may be very rough, but demonstrates a useful point on this subject.
Although it shows little about the rhythm in the narrow sense of that word (quavers and crotchets) it says much about how this variation plays with the rhythm of "Twinkle, Twinkle".
The notes of this theme are often pushed off the main beats - in the process of prolonging these structural notes, the diminutions delay their arrival. Schenkerian analysis does not only deal with pitches but with how pitches are used to structure time.