Blues Guitar Chords: 12-Bar Shapes and Turnarounds

Start blues guitar with E7, A7 and B7, then add D7 to move the same twelve-bar form into A. These open seventh shapes let you practise harmony, counting and feel separately. First play four even downstrokes per bar at a comfortable pace. Add quick changes and shuffle only after you can reach bar 12 without losing your place.

Four open seventh shapes to learn first

Read the fret numbers from string 6 to string 1; x means leave that string silent. The reference diagrams use the same grips as this table. Start E7 on string 6, A7 and B7 on string 5, and D7 on string 4.

The formula for a dominant seventh is 1–3–5–♭7. E7 has D rather than Emaj7’s D#, and A7 has G rather than Amaj7’s G#. Those lowered sevenths are part of the chosen sound. The number 7 does not tell you to fret at the seventh fret.

B7 is the busiest open grip here. Land its fingers without sounding the low sixth string, then test the open second-string B and first-string F# separately. Practise B7–E7 in a pair before expecting a whole twelve-bar cycle to fix the change for you. An open grip can still require several independent finger placements.

Count the twelve bars in E and A

The following is one common major-blues form with a V7 turnaround. Each row is one complete 4/4 bar, not one strum. The numeral identifies the root’s role; the 7 specifies the chosen chord quality. Read down the table, keeping four numbered beats in every bar.

Remember the route in three four-bar groups: stay home for four, move to IV7 for two and return for two, then play V7–IV7–I7–V7. There are twelve bars and 48 quarter-note beats. At quarter-note 60 BPM, a complete cycle lasts 48 seconds; changing the strumming density does not add or remove bars.

JustinGuitar’s twelve-bar lesson distinguishes this route from quick-change and other variants. Use the chart as a specific accompaniment exercise, not a claim that every song with blues in its title follows it. A song can also use an eight-bar, sixteen-bar or less regular form.

Change bar 2 or the ending deliberately

Learn one variation at a time. A quick change moves to IV7 in bar 2, then returns to I7 in bar 3. That is an earlier harmonic change, not a request to speed up. Keep the other eleven bars of this exercise unchanged while you learn it.

Tomas Michaud’s introductory lesson teaches the quick-change route in E and starts with one stroke per beat. Here the final E7 is our simple agreed ending. It replaces the V7 in bar 12; it is not an extra thirteenth bar. A turnaround is an approach back to the beginning and can contain more harmony than this single V7. No particular recording’s riff or turnaround lick is transcribed here.

Separate straight rhythm from shuffle feel

For the first pass, play only the four quarter-note downstrokes: 1, 2, 3, 4. Next say three equal subdivisions inside each beat, such as “one-trip-let.” A basic shuffle attacks the first and third triplet positions, leaving the middle position without a new attack. The first sound lasts through two triplet subdivisions and the second through one.

That 2:1 long-short relationship is a useful starting exercise. Keep the quarter-note pulse steady while changing the space between attacks. Robbie Calvo’s Yamaha rhythm lesson separates quarter notes, straight eighths, triplets and shuffle verbalizations. Listen to a teacher’s demonstration rather than assuming that alternating down and up automatically produces the right feel.

A twelve-bar form does not require shuffle: you can play it straight too. For this exercise count four large beats; writing triplet subdivisions as 12/8 would not turn one bar into three bars. The strumming-pattern tool is useful for straight-eighth hand coordination, while its evenly spaced cells should not be read as a literal long-short shuffle performance.

Move the harmony into A without sliding open strings

Use A7–D7–E7 for I7–IV7–V7 in A, as shown in the same twelve-row chart. The root roles remain the same even though their letters change. Open-string grips need their own fingerings: moving every fretted dot while leaving open strings unchanged does not transpose the entire chord. Look up the new grip rather than treating the nut as if it moved with your hand.

I7 and IV7 in this major-blues setting have dominant-seventh quality. They are not the diatonic Imaj7 and IVmaj7 of a harmonized major scale. For example, A7 includes G natural, while A major’s scale has G#. That does not make the chord a printing error. Am7 would change the third from C# to C, so it is another sound again. Minor-blues arrangements need their own changes; the table is not a universal substitution recipe.

Use the circle of fifths to locate roots and the chord builder to hear each seventh’s notes. The progression generator helps compare root relationships such as I–IV–V; its ordinary patterns do not supply the twelve-bar durations and dominant qualities in this chart.

A ten-minute practice routine

1. Spend two minutes testing each grip string by string. Alternate B7–E7, then A7–D7, stopping to correct muted melody strings or unwanted bass notes.
2. Spend three minutes with the metronome in 4/4 at quarter-note 60 BPM. Play the E column with four light downstrokes per bar, saying the bar number on beat 1. Lower the tempo if changes disturb the count.
3. Spend two minutes changing only bar 2 to A7. Then compare another full cycle with the main chart. Mark whether you reached the IV7 in bar 5 on time.
4. Spend three minutes on one-chord shuffle coordination, then apply it to the form if the pulse holds. Before the last cycle, agree whether bar 12 leads back with B7 or finishes on E7.

Record a complete cycle and check bar numbers before judging how many embellishments you played. A clean change at the right point is more useful than a fill that erases a beat. Once E is secure, repeat the routine in A. The broader chord-progression guide explains Roman numerals in other styles; the twelve-bar table here supplies the particular form to practise.