Your First Chords: Major, Minor, and the Dominant

Major and Minor: The Two Flavors

Every basic chord (a triad) is built the same way: stack two thirds on top of each other. Root, third, fifth. But the order of those thirds — which one comes first as you stack up from the root — changes everything.

• Major chord: the first third you stack (root to third) is a major third — four half steps. The second third (third to fifth) is a minor third — three half steps. Sounds bright, stable, resolved.
• Minor chord: the first third (root to third) is a minor third — three half steps. The second (third to fifth) is a major third — four half steps. Sounds darker, more emotional, less settled.

That’s it. One note — the third — is the difference between happy and sad, light and dark, resolved and yearning. Lower the third by a half step and a major chord becomes minor. Raise it and a minor chord becomes major. The root and fifth stay the same.

Try it on a keyboard. Play C–E–G (C major). Now play C–E♭–G (C minor). Hear the difference? That half step is doing all the work.

The IV and V Chords: The Two Forces

Both the IV chord and the V chord are special — they’re each a fifth away from the tonic, but in opposite directions. The V chord is a fifth up from I. The IV chord is a fifth down from I (or a fourth up — same thing). They’re like two arms reaching out from home in opposite directions.

But they don’t feel the same. The IV chord (F major in our key) shares a note with the I chord — both contain C. That shared note makes the IV feel stable next to the tonic, like a comfortable neighbor. The V chord (G major), on the other hand, does not contain the tonic note C. And that’s why it pulls so hard.

Play a G major chord, then play C major right after. Feel that? That pull, that sense of resolution — that’s the dominant function. The V chord creates tension, and the I chord (the tonic) releases it. This is the engine that drives most of Western music.

What makes it pull so hard? The third of the V chord. In the key of C, the V chord is G major, and its third is B — the seventh degree of the C major scale, also called the leading tone. That B note is one half step away from C, and it aches to get there. It has teeth — it grabs the tonic and won’t let go.

Four-Note Chords: Seventh Chords

So far every chord has been a triad — three notes, built by stacking two thirds. But you can keep stacking. Add one more third on top of the fifth and you get a seventh chord — four notes, a tetrad. That extra note changes the personality of the chord dramatically.

There are three types that matter right now:

• Major 7th (Cmaj7: C–E–G–B): A major triad with the note a half step below the octave on top. Sounds dreamy, open, a little sophisticated — like a chord wearing a nice jacket. Build one on the I chord and the IV chord and you’ll hear it instantly: Cmaj7, Fmaj7.

• Minor 7th (Dm7: D–F–A–C): A minor triad with a minor seventh on top. Sounds warm, mellow, a little hazy. Most of the minor chords in the key (ii, iii, vi) naturally become minor 7ths when you add the diatonic seventh: Dm7, Em7, Am7.

• Dominant 7th (G7: G–B–D–F): A major triad with a minor seventh on top. That mismatch — major chord, minor seventh — is what gives it its restless, unstable character. Only one chord in the key naturally produces this combination: the V chord.

The Dominant 7th: The One with Teeth

This is the chord that produces arguably the most important cadence in all of Western music. The dominant 7th deserves its own spotlight. It has two notes that want to resolve: the B wants to go up to C, and the F wants to come down to E. Those two notes — the third and the seventh of the chord — form a special interval called a tritone. The tritone is the most unstable interval in music. It needs to resolve. And when it does, it lands you squarely on the tonic.

Think of it this way: a plain G major chord is politely suggesting you go home. A G7 is insisting.

Here’s an analogy worth remembering — we’ll come back to it in a later chapter when it really pays off. A major chord without the seventh is like finding a dollar bill on the street — it could belong to anyone. You can’t tell where it came from or where it’s going. But a dominant 7th is like finding a wallet — it has an ID in it. Those leading tones tell you exactly where this chord lives and where it wants to go. Keep that in your back pocket (pun intended) — when we see more chords, the wallet analogy will become one of the most useful ideas in this course.

The Two Cadences

A cadence is a chord progression that brings the music to a landing — a moment of arrival. There are two that matter right now:

Perfect cadence (V → I): The dominant resolves to the tonic. This is the “Amen” of music — the strongest, most definitive ending. It’s the period at the end of a sentence. When the V chord pulls to the I chord, your ear says “we’re home.”

Plagal cadence (IV → I): The subdominant resolves to the tonic. This one is gentler — less of a snap and more of a sigh. If the perfect cadence is a period, the plagal cadence is an ellipsis. It’s the sound of a hymn ending (“A-men,” IV–I). It’s still a resolution, but it doesn’t have the same urgency as V–I.

Between these two forces — the pull of the dominant and the drift of the subdominant — you have the basic physics of how chords move. The V → I is urgent, directional, inevitable. The IV → I is gentle, warm, unhurried. Nearly everything you’ll encounter in popular music is some variation of these two forces.

The I, IV, V: Your First Progression

With just three chords — I, IV, and V — you can play an enormous amount of music. The blues. Early rock and roll. Country. Countless folk songs. Three chords and the truth, as the saying goes.

In the key of C:

• I = C major (home)
• IV = F major (the moon)
• V = G major, or G7 (the sun)

Play I–IV–V–I. That’s a whole journey: you start home, you wander, you get pulled back, you arrive. That cycle — tension and release, departure and return — is the fundamental story that music tells, over and over, in infinite variations.

I → IV → V → I on the Harmony Wheel — hear the journey.

Adding the vi Chord

There’s one more chord that shows up in almost everything: the vi chord — the chord built on the sixth degree. In C major, that’s A minor.

The vi is the relative minor of the key. It shares two of its three notes with the I chord (C major has C–E–G; A minor has A–C–E). That’s why it feels related — familiar but darker. Moving from I to vi feels like the music has turned a corner, shifted its mood without leaving the neighborhood.

With I, IV, V, and vi, you can play most pop songs written in the last sixty years. Seriously. Those four chords — in various orders — are the backbone of an absurd amount of music. We’ll dig into exactly how much in a later chapter.

I → V → vi → IV on the Harmony Wheel — the most popular chord progression in modern music.

What’s Next

We now have the vocabulary (intervals, scale degrees, chord tones), the two forces that move music (dominant pull and subdominant drift), and four chords to play with. In the next chapter, we’re going to start building out the full 10 Chord Toolkit — and the first stop is a song you definitely know.