Dominant 7ths are not always on V

The Three Chord Trick

In this chapter, The Three Chord Trick, we're going to look at tunes that feature I, IV, and V chords. These three chords are like the backbone of Western music. You can find many folk, popular, traditional tunes, and hymns, for instance, that use nothing but these three chords.

If you're playing:

• Pop
• Soul
• R&B
• Jazz
• Blues
• Gospel
• Reggae
• Rock and Roll
• Calypso

All these styles have a lot of tunes that only use those three chords.

While the I and IV chords may indeed just be triads, the V chord is often a dominant seventh.

Chords in the Key of G

So you might have:

• I chord: G
• IV chord: C
• V chord: D7 (often with a seventh)

A good example of this type of tune is "Suwanee River," which we'll be playing next.

Perfect Cadence

Dominant seventh chords always want to resolve up a fourth, like:

• D7 to G.

That's called a perfect cadence. You can play that in different positions and inversions, but the root is always going up a fourth, from D to G.

In "Suwanee River," we also have an unexpected dominant chord on one, like G7 instead of G major seven. This is because it's taking us to C, with C being the IV chord in the key of G.

The dominant seventh and the perfect cadence can take you to other places, in this case, from I to IV instead of V to I.

Two Ways to Transition

Now, there are two ways of doing this, which are kind of neat:

1. Descending Bass Line:

   • Play your G chord.
   • Move to G7 with F in the bass.
   • This takes you to C with E in the bass.

   You can write that with slash chords if you like:

   • G7 over F
   • C7 over E

2. Rising Bass Line:

   • Start with a root position G down here.
   • Go to A first inversion with B in the bass.
   • This takes us to C in root position.

   This implies a rising bass line:

   • G7 over B

These are two different ways of going from G via G7 to the IV chord C major.

This slash chord notation is often employed in chord charts or lead sheets as a way of specifying this type of chord movement.