Twelve-bar blues twelve bars, three chords
The twelve-bar blues is the song form most rock, jazz and soul players learned on. Three chords, a swung feel, and a short scale with one bent-sounding note — it puts your open sevenths, strumming and the pentatonic into one place. Everything here is in C; Play along has the same form in G.
The form
Twelve bars of four beats. I is C7, IV is F7, V is G7 (the numbers are explained on Chords in a key):
| Bars 1–4 | C7 | C7 | C7 | C7 |
|---|---|---|---|---|
| Bars 5–8 | F7 | F7 | C7 | C7 |
| Bars 9–12 | G7 | F7 | C7 | G7 |
Bar 12 on the V is the turnaround: it pulls you back to bar 1. On the last time through, end on C7 instead. Many players go to the IV for bar 2 — the quick change — and the form is otherwise the same.
The three shapes
Frets read G · C · E · A.
- C7 — 0 0 0 1. One finger: index on A fret 1.
- F7 — 2 3 1 0. Index on E fret 1, middle on G fret 2, ring on C fret 3.
- G7 — 0 2 1 2. The same one you know from Open chords.
The shuffle feel
Count each beat in three — 1-trip-let 2-trip-let — and strum only on the first and last of each three: a long down, a short up. Long, short, long, short. That uneven pair is the shuffle; written music shows plain eighths and a note saying swing. Keep the wrist loose and let the up-strum catch only the top two strings.
Soloing — the blues scale
C blues in first position: C E♭ F G♭ G B♭ C, up and back down. The G♭ (the ♭5) is the blue note — it is a passing note, so slide through it and do not park on it. Every fret here is 0–3.
A|------------|-----1--3--1|------------|---|
E|--------1--2|--3---------|--3--2--1---|---|
C|--0--3------|------------|-----------3|--0|
G|------------|------------|------------|---|
C Eb F Gb G Bb C Bb G Gb F Eb C
Call and response
Blues phrases talk in pairs: a question and an answer. Play the call, then answer from where it stopped. The call ends open, on F; the answer walks down through the blue note and lands home on C.
A|---------|------------|---|
E|--------1|--3--2--1---|---|
C|--0--3---|-----------3|--0|
G|---------|------------|---|
C Eb F G Gb F Eb C
Then make your own: keep the call, change the answer. Improv picks this up with target notes, and Backing band has blues loops.
Ready when
Move on when all of these are true on a normal day, not your best one:
- You can say where you are in the twelve bars without counting from bar 1.
- C7 → F7 → G7 changes on time with a real shuffle, not straight eighths.
- You can play the C blues scale up and down, answer a call of your own, and land on C at bar 11.