Chords in a Major Key

The key identifies a scale

The key of a song identifies its scale. For example, a song in the key of E major uses the E major scale (a major scale pattern starting on the note E). Here's the E major scale on the sixth string:

Chord roots on scale tones

Each note of the scale is the root of a chord, derived by harmonizing the scale.

• Major chords are rooted on the 1, 4, and 5 notes of the scale. They're called the I, IV, and V chords.
• Minor chords are rooted on the 2, 3, and 6 notes of the scale. They're called the ii, iii, and vi chords.
• The chord rooted on 7 is a diminished chord, which won't be covered here.

Notice that the chords in a key are identified by Roman numerals; uppercase for major chords, and lowercase for minor chords.

E-shape chords in the key

Place an E-shape major or minor chord on each note in the scale to play each chord in the key.

This works for any major key. Just change the starting note of the scale. Open the diagram settings and experiment with changing keys and showing note names in overlay labels.

Notice that this example doesn't play a chord on the 7. It plays a V7 chord instead (an E7-shape chord on the 5). The V7 and vii° chords are very similar, and the V7 is much more common. See Dominant Function for details.