Twelve-bar blues twelve bars, three roots

The twelve-bar blues is the song form most rock, jazz and soul bands start on. Three chords and a swung feel — and on bass it is where roots, the fifth and the sixth, and the shuffle all meet. This page is the foundation; Walking bass is where the quarter-note line takes over. Everything here is in A.

The form

Twelve bars of four beats. I is A7, IV is D7, V is E7 (the numbers are explained on Chords in a key). You play the root:

Bars 1–4A7A7A7A7
Bars 5–8D7D7A7A7
Bars 9–12E7D7A7E7

Bar 5 is the first landmark: the move to the IV. Bar 9 is the second, the V. Bar 12 is the turnaround: it pulls you back to bar 1. On the last time through, end on A7.

The shuffle feel

Count each beat in three — 1-trip-let 2-trip-let — and play only the first and last of each three. Long, short, long, short. That uneven pair is the shuffle; written music shows plain eighths and a note saying swing. Sit it on the drummer’s ride, not on top of it.

G|------------------------|
D|------------------------|
A|--0--0--0--0--0--0--0--0|
E|------------------------|
    A  A  A  A  A  A  A  A

The shuffle line — 1 3 5 6 ♭7 6 5 3

One bar, eight swung eighths: climb the chord — root, third, fifth, sixth, flat seventh — and come back down. It is the stock blues line, and the same pattern from each chord’s root. Keep the hand where it is; every note sits within five frets of the root.

A7 — A C♯ E F♯ G F♯ E C♯

G|------------------------|
D|--------2--4--5--4--2---|
A|--0--4-----------------4|
E|------------------------|
    A C#  E F#  G F#  E C#

D7 — D F♯ A B C B A F♯

G|--------2--4--5--4--2---|
D|--0--4-----------------4|
A|------------------------|
E|------------------------|
    D F#  A  B  C  B  A F#

E7 — E G♯ B C♯ D C♯ B G♯

G|------------------------|
D|------------------------|
A|--------2--4--5--4--2---|
E|--0--4-----------------4|
    E G#  B C#  D C#  B G#

The line through all twelve bars

One bar of the line per bar of the form. Follow the table above and say the chord on each beat 1. Tempo comes from the practice bar — start at 70.

Soloing — the blues scale

A blues scale: A C D E♭ E G A. The E♭ (the ♭5) is a passing note — slide through it, do not park on it. The full map is on Scales.

G|------------|---------|
D|------------|-----5--7|
A|--0--3--5--6|--7------|
E|------------|---------|
    A  C  D Eb   E  G  A

Call and response

Blues phrases talk in pairs: a question, then an answer. The call ends open on D; the answer falls through the blue note and lands home on A.

G|---------|------------|---|
D|---------|--2---------|---|
A|--0--3--5|-----6--5--3|--0|
E|---------|------------|---|
    A  C  D   E Eb  D  C   A

Then make your own: keep the call, change the answer. Lead bass takes the idea up the neck, 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.
  • The shuffle line moves A → D → E on time with a real shuffle, not straight eighths.
  • You can play the roots through a chorus and land on A at bar 11 with the turnaround on bar 12.
Sources: the standard twelve-bar I–IV–V dominant form, the 1–3–5–6–♭7 shuffle line and the ♭5 blue note. Fingerings are checked against standard tuning, E A D G; lines are original.

Text twin: blues.md