One of the best lines in the Broadway musical The Music Man, is when the traveling salesmen are on the train, musing on how to be successful at their trade. “You gotta know the territory” they emphatically tell each other, implying that each town is different and that a successful salesman is one who takes the time to study each locality in detail before arriving there. It’s a great scene, and if you haven’t seen it before, you can enjoy it here:

The Music Man (Opening scene)

We pianists “gotta know the territory” as well, and for us, this means knowing each genre we play inside and out.

A good example of this involves the idiomatic use of dominant preparation chords.

A lot of chord progressions begin with the tonic, go somewhere else, and then go to the dominant (V) chord which leads us “home” to the tonic (I) again. This harmonic cycle appears in music ranging from Bach to Ed Sheeran. It’s all over jazz and blues too. The chord before the dominant is what we’re focusing on here.

Let’s look at this in the key of C major:

The long arc of the harmonic progression is that we begin on a C chord, which is the tonic, then we eventually get to the G chord (dominant), which pushes us home to the tonic again. Along the way, we can insert other harmonies before the dominant which in a sense “prepare” us for it. This is the spot we’re investigating right now. The dominant preparation chord is often either a ii (Dm) or IV (F) chord.

The key is to know which one to use in each musical genre.

Let’s look at three contrasting styles of music: jazz, rock, and classical.

Which dominant prep chord is characteristic of each of these genres?

In jazz, it’s usually a Dm7 chord, leading to a progression such as: Cmaj7/Dm7/G7/Cmaj7.

In rock, it’s usually an F chord, which gives us the more “primal” sound of C/F/G/C.

Classical composers used the ii chord like in jazz, but they inverted it to avoid parallel fifths:
C/Dm in inversion/G7/C. Have a look at the beginning of Bach’s famous C Major Prelude to see this in action:

Bach: C Major Prelude

In music, as in The Music Man, we “gotta know the territory.”

Enjoy the journey, and “let the music flow!”

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