Reading a Chord — Wedges and Function

The functions on the wheel

In any key, the wheel lays out the chords you actually use:

• I, ii, iii, IV, V, V7, vi, vii° — the diatonic chords, the seven built from the scale.
• iv — the borrowed minor subdominant (the “minor four” that gives that bittersweet pull).
• ♭VII — the flat-seven, a common borrowed major chord.
• V/V and V/vi — secondary dominants: dominant chords that point at a chord other than the tonic. V/V is “the dominant of the dominant”; V/vi sets up the relative minor. (The Music Theory guide builds these up step by step.)
• Bonus wedges V/ii and ii/vi — two more secondary functions you can switch on (see the Mic & Bonus chapter).

You don’t have to memorize that list — the point of the wheel is that you see it. Play through a song and watch which wedges light: you’re reading its harmony in real time.

The three colors

The wedges are grouped by color into the three jobs a chord can do:

• Tonic — home. Rest, resolution, arrival (I, and its stand-ins vi and iii).
• Predominant — the build. Chords that set up tension and lead toward the dominant (ii, IV, iv).
• Dominant — the pull. Chords that strain to resolve home (V, V7, vii°).

This is the heartbeat of functional harmony: home → tension → pull → home. Once the colors are in your eye, you can glance at any progression and see its shape — where it’s resting, where it’s building, where it’s about to resolve.

Clicking a wedge

The wheel isn’t only for listening — click any wedge and it previews that chord: you’ll hear it (through the preview synth) and see its notes on the keyboard. That makes the wheel a way to explore a key, not just analyze one. Want to know what the ♭VII sounds like in your key? Click it. Curious how V/vi sets up the relative minor? Click V/vi, then vi, and hear the pull.

What to Practice

• Play a I–IV–V–I in any key and watch the wedges light in turn. Name the color of each as it goes.
• Click around the wheel — the borrowed chords (iv, ♭VII) and the secondary dominants (V/V, V/vi) — to hear functions you might not reach for by habit.
• Play a song you know and just watch the colors. Notice how often it’s home → predominant → dominant → home.