# Chords in a key

A key is a scale; stacking thirds on each scale note gives seven chords that belong together. Number them and every key reads the same.

## Seven chords from one scale

I major · ii minor · iii minor · IV major · V major · vi minor · vii° diminished. In C: C Dm Em F G Am B°. Six of the seven are on [Open chords](chords.md).

## The keys you will meet first

| Key | I | ii | iii | IV | V | vi | vii° |
|---|---|---|---|---|---|---|---|
| C | C | Dm | Em | F | G | Am | B° |
| G | G | Am | Bm | C | D | Em | F♯° |
| F | F | Gm | Am | B♭ | C | Dm | E° |
| D | D | Em | F♯m | G | A | Bm | C♯° |
| A | A | Bm | C♯m | D | E | F♯m | G♯° |

## Progressions by number

- I–IV–V–I (C F G C)
- I–V–vi–IV (C G Am F)
- vi–IV–I–V (Am F C G)
- I–vi–IV–V (C Am F G)
- ii–V7–I (Dm G7 C) — see [Jazz](jazz.md)

## Why V wants to go home

V holds the leading tone, a half step under the root. V7 doubles the pull: G7 → C; E7 → Am.

## Minor keys

The relative minor is the vi. Minor songs often borrow a major V (E7 in A minor) from harmonic minor.

## Transpose with a capo

Capo 2 + C–F–G shapes = I–IV–V in D.

## Find the key of a song

List the chords, find the row holding them all, check the last chord. C F G Am → C; G C D Em → G; Am F C G ending on Am → A minor.

## Ready when

- I, IV, V and vi of C, G, F, D and A without the table.
- Name a song's key from its chords and move it with a capo.
- Hear a progression land on V and expect the I.