by Gary Ewer, from “The Essential Secrets of Songwriting” Website:
Once you know what key your new song is going to be in, it’s a fairly simple process to figure out the triads (chords) that easily work in that key. You’ll find that the I (key) chord, the IV chord (based on the 4th note) and the V-chord (based on the 5th note) are going to be used more than the others. So let’s look at this a bit.
If your song is in G major, build a triad above each note of the scale. A triad is a 3-note chord, where each note is three notes above the one immediately below. So building a triad on the note G gives us G-B-D. Here, then, are the chords that naturally exist in the key of G major:
Of these chords, you will find that certain ones will be more used than others. The G is the most common because it represents your key of choice. In addition, the C (IV) and the D (V) chords will be used frequently. These three chords are the ones you hear people talking about when they mention the typical “3-chord song”. I like the analogy of the I-chord feeling like your house, the IV-chord feeling like the sidewalk near your house, and the V-chord feeling like your front door-step as you are about to step back into your house (the I-chord).
So what about the other chords: the ii-chord (Am), iii-chord (Bm), the vi-chord (Em) and the vii-chord (F#dim)? They are used a little less, with the F# diminished chord possibly the least-used of the bunch. But they certainly can work nicely for various reasons and for different situations. The ii-chord works as a nice substitution for the IV-chord, and the vi-chord can act as a substitution for the I-chord. When replacing the I-chord with vi, we call that a “deceptive cadence.” Here are some chord progressions that use these chords in various ways. Feel free to use or adapt them for your own use:
1) G Em C D G
2) This one substitutes the IV (C) with a ii (Am):
G Em Am D G
3) This one uses a chord inversion (G/B) which means to play a G chord with the note B as its lowest sounding pitch:
G G/B C Em Am D G
4) G C C/E D/F# G
5) This one uses Em as a final chord, the so-called “deceptive cadence”:
G D/F# Em G/B C D Em
So to discover the chords that will automatically work with the key you’ve chosen, simply build 3-note chords above each note of the major scale, and you’ve got your set of chord for that song. Then the next step (a subject for the next article on this site) is to start adding interesting “altered chords” to broaden your song’s harmonic palette. If you want to read about how to solve your songwriting woes, get Gary’s suite of 5 songwriting e-books. Right now, they’re being offered as a bundle for a fraction of the cover price! Click here to learn more..