The 10 Chord Toolkit: Part 1

Hey Jude: Now It Has a Name

You already saw this in Chapter 1: in “Hey Jude,” the C chord starts as the tonic, then adds a B♭ to become C7 — a dominant seventh aimed at F. Same chord, different job. Structure vs. function.

Now that move has a name. When C7 resolves to F, it’s acting as the V of IV — a dominant chord aimed at a target other than the tonic. That’s a secondary dominant. It borrows the dominant-to-tonic pull and points it somewhere else. For just a moment, the song pretends it’s in the key of F, uses the pull to get there, and carries on.

This is one of the most common and powerful tools in all of songwriting.

Secondary Dominants: The Chain

Here’s the big idea: every chord can have its own V chord. We’ve been calling the V chord the “dominant” — the chord that pulls hardest toward home. A secondary dominant borrows that same pull and aims it at a chord other than I.

The notation makes more sense once you remember that V = dominant. When you see V/vi, read it as “the dominant of the vi chord.” It’s a V chord, just pointed at a different target.

The most common ones:

• V/vi — the dominant of the vi chord. In the key of C, that’s E7, resolving to A minor. The relative minor is important enough to deserve its own dominant — its own doorbell. Without one, A minor only has the iii chord (Em) leading to it, which is minor — no leading tone, no teeth. E7 fixes that. It gives A minor a proper dominant with real pull.

• V/V — the dominant of the dominant. In C, that’s D7, resolving to G7, which then resolves to C. It’s a chain: D7 → G7 → C, or in numbers, V/V → V → I. Think of “12 Days of Christmas” — that moment when it reaches “Five Golden Rings!” That’s the V/V pulling hard into the V before resolving home. Juke boxes and Broadway songs live in this space.

You can keep chaining: V/V/V, V/V/V/V — in theory, forever. Each dominant resolves to the next one down the line. In practice, the chain usually goes two or three deep at most. But the concept is what matters: dominant chords don’t just resolve to I. They resolve to whatever chord they’re built to aim at.

The Wallet Analogy, Revisited

Remember the wallet vs. dollar analogy from last chapter? A plain major chord is a dollar bill — you can’t tell where it belongs. But a dominant 7th is a wallet with ID. Those leading tones (the third and the seventh) tell you exactly where it’s headed.

Secondary dominants are wallets aimed at different addresses. The ID is always in the same place — the third and the seventh of the chord. Those two notes are the leading tones, and they tell you exactly where the chord is headed.

E7 (E–G#–B–D): G# wants to go up a half step to A. D wants to come down to E. Those two notes pull you straight to A minor.

D7 (D–F#–A–C): F# wants to go up a half step to G. C wants to come down to B. Those pull you to G major.

The wallet always tells you where the chord wants to land.

This is huge. When you hear a new chord that sounds “outside” the key — a note that doesn’t belong to the scale — the first question to ask is: is this a wallet? And if so, whose address is in it?

The Relative Minor: vi as a Second Home

We already know the vi chord (A minor in the key of C). But secondary dominants reveal something deeper about it: the vi can function as a secondary tonic. It has its own dominant (V/vi = E7), its own subdominant (Dm = iv of vi), its own little gravitational system.

In fact, the relationship between C major and A minor is so close that they share the exact same set of notes — the same scale, just starting on a different note. This is the relative minor relationship. Count three white keys down from C and you land on A. Count three white keys up from A and you’re back at C. The relative minor always lives on the sixth degree — that’s why it’s the vi chord.

This dual-numbering can get confusing. A minor is vi when you’re thinking in C major, but it’s i when you’re thinking in A minor. Both are correct — it depends on which key you’re in. Context, again, is everything.

Inversions: Same Chord, Different Bass Note

Before we add more chords to the toolkit, there’s one more concept you need: inversions.

A chord in root position has the root on the bottom: C–E–G. But you can rearrange the notes so a different chord tone is on the bottom:

• First inversion: the third is on the bottom — E–G–C
• Second inversion: the fifth is on the bottom — G–C–E

It’s still a C major chord. The notes are the same. But the sound changes — the bass note affects how stable, how grounded, how “open” the chord feels. Root position is solid. First inversion is lighter, more flowing. Second inversion is floating, almost unstable.

Inversions are how chord progressions move smoothly. Instead of jumping from one root-position chord to another (which works, but can sound blocky), you can rearrange the notes so that each chord shares common tones with the one before it — and the ones that do move only travel a short distance. This smooth motion between chords is called voice leading, and it’s going to become a major topic later in the course.

For now, just know: a chord can appear in different arrangements, and the bass note matters.

Where We Are

After this chapter, your toolkit includes:

Six chords. Four more to go. Next chapter, we fill in the rest.